fix: Port upstream cover extraction fallback and outline improvements

Port PR #838 (epub cover fallback logic) and PR #907 (cover outlines):

- Add fallback cover filename probing when EPUB metadata lacks cover info
- Case-insensitive extension checking for cover images
- Detect and re-generate corrupt/empty thumbnail BMPs
- Always draw outline rect on cover tiles for legibility (PR #907)
- Upgrade Storage.exists() checks to Epub::isValidThumbnailBmp()
- Fallback chain: Real Cover → PlaceholderCoverGenerator → X-pattern marker
- Add epub.load retry logic (cache-only first, then full build)
- Adapt upstream Serial.printf calls to LOG_DBG/LOG_ERR macros

Co-authored-by: Cursor <cursoragent@cursor.com>

lib/Epub/Epub.cpp

@@ -1,11 +1,14 @@
 #include "Epub.h"
 
 #include <FsHelpers.h>
+#include <HalDisplay.h>
 #include <HalStorage.h>
 #include <JpegToBmpConverter.h>
 #include <Logging.h>
 #include <ZipFile.h>
 
+#include <algorithm>
+
 #include "Epub/parsers/ContainerParser.h"
 #include "Epub/parsers/ContentOpfParser.h"
 #include "Epub/parsers/TocNavParser.h"
@@ -208,30 +211,14 @@ bool Epub::parseTocNavFile() const {
   return true;
 }
 
-std::string Epub::getCssRulesCache() const { return cachePath + "/css_rules.cache"; }
-
-bool Epub::loadCssRulesFromCache() const {
-  FsFile cssCacheFile;
-  if (Storage.openFileForRead("EBP", getCssRulesCache(), cssCacheFile)) {
-    if (cssParser->loadFromCache(cssCacheFile)) {
-      cssCacheFile.close();
-      LOG_DBG("EBP", "Loaded CSS rules from cache");
-      return true;
-    }
-    cssCacheFile.close();
-    LOG_DBG("EBP", "CSS cache invalid, reparsing");
-  }
-  return false;
-}
-
 void Epub::parseCssFiles() const {
   if (cssFiles.empty()) {
     LOG_DBG("EBP", "No CSS files to parse, but CssParser created for inline styles");
   }
 
-  // Try to load from CSS cache first
-  if (!loadCssRulesFromCache()) {
-    // Cache miss - parse CSS files
+  // See if we have a cached version of the CSS rules
+  if (!cssParser->hasCache()) {
+    // No cache yet - parse CSS files
     for (const auto& cssPath : cssFiles) {
       LOG_DBG("EBP", "Parsing CSS file: %s", cssPath.c_str());
 
@@ -262,11 +249,10 @@ void Epub::parseCssFiles() const {
     }
 
     // Save to cache for next time
-    FsFile cssCacheFile;
-    if (Storage.openFileForWrite("EBP", getCssRulesCache(), cssCacheFile)) {
-      cssParser->saveToCache(cssCacheFile);
-      cssCacheFile.close();
+    if (!cssParser->saveToCache()) {
+      LOG_ERR("EBP", "Failed to save CSS rules to cache");
     }
+    cssParser->clear();
 
     LOG_DBG("EBP", "Loaded %zu CSS style rules from %zu files", cssParser->ruleCount(), cssFiles.size());
   }
@@ -279,11 +265,11 @@ bool Epub::load(const bool buildIfMissing, const bool skipLoadingCss) {
   // Initialize spine/TOC cache
   bookMetadataCache.reset(new BookMetadataCache(cachePath));
   // Always create CssParser - needed for inline style parsing even without CSS files
-  cssParser.reset(new CssParser());
+  cssParser.reset(new CssParser(cachePath));
 
   // Try to load existing cache first
   if (bookMetadataCache->load()) {
-    if (!skipLoadingCss && !loadCssRulesFromCache()) {
+    if (!skipLoadingCss && !cssParser->hasCache()) {
       LOG_DBG("EBP", "Warning: CSS rules cache not found, attempting to parse CSS files");
       // to get CSS file list
       if (!parseContentOpf(bookMetadataCache->coreMetadata)) {
@@ -457,9 +443,18 @@ std::string Epub::getCoverBmpPath(bool cropped) const {
 }
 
 bool Epub::generateCoverBmp(bool cropped) const {
+  bool invalid = false;
   // Already generated, return true
   if (Storage.exists(getCoverBmpPath(cropped).c_str())) {
-    return true;
+    // is this a valid cover or just an empty file we created to mark generation attempts?
+    invalid = !isValidThumbnailBmp(getCoverBmpPath(cropped));
+    if (invalid) {
+      // Remove the old invalid cover so we can attempt to generate a new one
+      Storage.remove(getCoverBmpPath(cropped).c_str());
+      LOG_DBG("EBP", "Previous cover generation attempt failed for %s mode, retrying", cropped ? "cropped" : "fit");
+    } else {
+      return true;
+    }
   }
 
   if (!bookMetadataCache || !bookMetadataCache->isLoaded()) {
@@ -468,13 +463,33 @@ bool Epub::generateCoverBmp(bool cropped) const {
   }
 
   const auto coverImageHref = bookMetadataCache->coreMetadata.coverItemHref;
+  std::string effectiveCoverImageHref = coverImageHref;
   if (coverImageHref.empty()) {
+    // Fallback: try common cover filenames
+    std::vector<std::string> coverCandidates = getCoverCandidates();
+    for (const auto& candidate : coverCandidates) {
+      effectiveCoverImageHref = candidate;
+      // Try to read a small amount to check if exists
+      uint8_t* test = readItemContentsToBytes(candidate, nullptr, false);
+      if (test) {
+        free(test);
+        break;
+      } else {
+        effectiveCoverImageHref.clear();
+      }
+    }
+  }
+  if (effectiveCoverImageHref.empty()) {
     LOG_ERR("EBP", "No known cover image");
     return false;
   }
 
-  if (coverImageHref.substr(coverImageHref.length() - 4) == ".jpg" ||
-      coverImageHref.substr(coverImageHref.length() - 5) == ".jpeg") {
+  // Check for JPG/JPEG extensions (case insensitive)
+  std::string lowerHref = effectiveCoverImageHref;
+  std::transform(lowerHref.begin(), lowerHref.end(), lowerHref.begin(), ::tolower);
+  bool isJpg =
+      lowerHref.substr(lowerHref.length() - 4) == ".jpg" || lowerHref.substr(lowerHref.length() - 5) == ".jpeg";
+  if (isJpg) {
     LOG_DBG("EBP", "Generating BMP from JPG cover image (%s mode)", cropped ? "cropped" : "fit");
     const auto coverJpgTempPath = getCachePath() + "/.cover.jpg";
 
@@ -482,7 +497,7 @@ bool Epub::generateCoverBmp(bool cropped) const {
     if (!Storage.openFileForWrite("EBP", coverJpgTempPath, coverJpg)) {
       return false;
     }
-    readItemContentsToStream(coverImageHref, coverJpg, 1024);
+    readItemContentsToStream(effectiveCoverImageHref, coverJpg, 1024);
     coverJpg.close();
 
     if (!Storage.openFileForRead("EBP", coverJpgTempPath, coverJpg)) {
@@ -516,9 +531,18 @@ std::string Epub::getThumbBmpPath() const { return cachePath + "/thumb_[HEIGHT].
 std::string Epub::getThumbBmpPath(int height) const { return cachePath + "/thumb_" + std::to_string(height) + ".bmp"; }
 
 bool Epub::generateThumbBmp(int height) const {
+  bool invalid = false;
   // Already generated, return true
   if (Storage.exists(getThumbBmpPath(height).c_str())) {
-    return true;
+    // is this a valid thumbnail or just an empty file we created to mark generation attempts?
+    invalid = !isValidThumbnailBmp(getThumbBmpPath(height));
+    if (invalid) {
+      // Remove the old invalid thumbnail so we can attempt to generate a new one
+      Storage.remove(getThumbBmpPath(height).c_str());
+      LOG_DBG("EBP", "Previous thumbnail generation attempt failed for height %d, retrying", height);
+    } else {
+      return true;
+    }
   }
 
   if (!bookMetadataCache || !bookMetadataCache->isLoaded()) {
@@ -527,56 +551,246 @@ bool Epub::generateThumbBmp(int height) const {
   }
 
   const auto coverImageHref = bookMetadataCache->coreMetadata.coverItemHref;
+  std::string effectiveCoverImageHref = coverImageHref;
   if (coverImageHref.empty()) {
+    // Fallback: try common cover filenames
+    std::vector<std::string> coverCandidates = getCoverCandidates();
+    for (const auto& candidate : coverCandidates) {
+      effectiveCoverImageHref = candidate;
+      // Try to read a small amount to check if exists
+      uint8_t* test = readItemContentsToBytes(candidate, nullptr, false);
+      if (test) {
+        free(test);
+        break;
+      } else {
+        effectiveCoverImageHref.clear();
+      }
+    }
+  }
+  if (effectiveCoverImageHref.empty()) {
     LOG_DBG("EBP", "No known cover image for thumbnail");
-  } else if (coverImageHref.substr(coverImageHref.length() - 4) == ".jpg" ||
-             coverImageHref.substr(coverImageHref.length() - 5) == ".jpeg") {
-    LOG_DBG("EBP", "Generating thumb BMP from JPG cover image");
-    const auto coverJpgTempPath = getCachePath() + "/.cover.jpg";
-
-    FsFile coverJpg;
-    if (!Storage.openFileForWrite("EBP", coverJpgTempPath, coverJpg)) {
-      return false;
-    }
-    readItemContentsToStream(coverImageHref, coverJpg, 1024);
-    coverJpg.close();
-
-    if (!Storage.openFileForRead("EBP", coverJpgTempPath, coverJpg)) {
-      return false;
-    }
-
-    FsFile thumbBmp;
-    if (!Storage.openFileForWrite("EBP", getThumbBmpPath(height), thumbBmp)) {
-      coverJpg.close();
-      return false;
-    }
-    // Use smaller target size for Continue Reading card (half of screen: 240x400)
-    // Generate 1-bit BMP for fast home screen rendering (no gray passes needed)
-    int THUMB_TARGET_WIDTH = height * 0.6;
-    int THUMB_TARGET_HEIGHT = height;
-    const bool success = JpegToBmpConverter::jpegFileTo1BitBmpStreamWithSize(coverJpg, thumbBmp, THUMB_TARGET_WIDTH,
-                                                                             THUMB_TARGET_HEIGHT);
-    coverJpg.close();
-    thumbBmp.close();
-    Storage.remove(coverJpgTempPath.c_str());
-
-    if (!success) {
-      LOG_ERR("EBP", "Failed to generate thumb BMP from JPG cover image");
-      Storage.remove(getThumbBmpPath(height).c_str());
-    }
-    LOG_DBG("EBP", "Generated thumb BMP from JPG cover image, success: %s", success ? "yes" : "no");
-    return success;
   } else {
-    LOG_ERR("EBP", "Cover image is not a supported format, skipping thumbnail");
+    // Check for JPG/JPEG extensions (case insensitive)
+    std::string lowerHref = effectiveCoverImageHref;
+    std::transform(lowerHref.begin(), lowerHref.end(), lowerHref.begin(), ::tolower);
+    bool isJpg =
+        lowerHref.substr(lowerHref.length() - 4) == ".jpg" || lowerHref.substr(lowerHref.length() - 5) == ".jpeg";
+    if (isJpg) {
+      LOG_DBG("EBP", "Generating thumb BMP from JPG cover image");
+      const auto coverJpgTempPath = getCachePath() + "/.cover.jpg";
+
+      FsFile coverJpg;
+      if (!Storage.openFileForWrite("EBP", coverJpgTempPath, coverJpg)) {
+        return false;
+      }
+      readItemContentsToStream(effectiveCoverImageHref, coverJpg, 1024);
+      coverJpg.close();
+
+      if (!Storage.openFileForRead("EBP", coverJpgTempPath, coverJpg)) {
+        return false;
+      }
+
+      FsFile thumbBmp;
+      if (!Storage.openFileForWrite("EBP", getThumbBmpPath(height), thumbBmp)) {
+        coverJpg.close();
+        return false;
+      }
+      // Use smaller target size for Continue Reading card (half of screen: 240x400)
+      // Generate 1-bit BMP for fast home screen rendering (no gray passes needed)
+      int THUMB_TARGET_WIDTH = height * 0.6;
+      int THUMB_TARGET_HEIGHT = height;
+      const bool success = JpegToBmpConverter::jpegFileTo1BitBmpStreamWithSize(coverJpg, thumbBmp, THUMB_TARGET_WIDTH,
+                                                                               THUMB_TARGET_HEIGHT);
+      coverJpg.close();
+      thumbBmp.close();
+      Storage.remove(coverJpgTempPath.c_str());
+
+      if (!success) {
+        LOG_ERR("EBP", "Failed to generate thumb BMP from JPG cover image");
+        Storage.remove(getThumbBmpPath(height).c_str());
+      }
+      LOG_DBG("EBP", "Generated thumb BMP from JPG cover image, success: %s", success ? "yes" : "no");
+      return success;
+    } else {
+      LOG_ERR("EBP", "Cover image is not a supported format, skipping thumbnail");
+    }
   }
 
-  // Write an empty bmp file to avoid generation attempts in the future
-  FsFile thumbBmp;
-  Storage.openFileForWrite("EBP", getThumbBmpPath(height), thumbBmp);
-  thumbBmp.close();
   return false;
 }
 
+bool Epub::generateInvalidFormatThumbBmp(int height) const {
+  // Create a simple 1-bit BMP with an X pattern to indicate invalid format.
+  // This BMP is a valid 1-bit file used as a marker to prevent repeated
+  // generation attempts when conversion fails (e.g., progressive JPG).
+  const int width = height * 0.6;                // Same aspect ratio as normal thumbnails
+  const int rowBytes = ((width + 31) / 32) * 4;  // 1-bit rows padded to 4-byte boundary
+  const int imageSize = rowBytes * height;
+  const int fileSize = 14 + 40 + 8 + imageSize;  // Header + DIB + palette + data
+  const int dataOffset = 14 + 40 + 8;
+
+  FsFile thumbBmp;
+  if (!Storage.openFileForWrite("EBP", getThumbBmpPath(height), thumbBmp)) {
+    return false;
+  }
+
+  // BMP file header (14 bytes)
+  thumbBmp.write('B');
+  thumbBmp.write('M');
+  thumbBmp.write(reinterpret_cast<const uint8_t*>(&fileSize), 4);
+  uint32_t reserved = 0;
+  thumbBmp.write(reinterpret_cast<const uint8_t*>(&reserved), 4);
+  thumbBmp.write(reinterpret_cast<const uint8_t*>(&dataOffset), 4);
+
+  // DIB header (BITMAPINFOHEADER - 40 bytes)
+  uint32_t dibHeaderSize = 40;
+  thumbBmp.write(reinterpret_cast<const uint8_t*>(&dibHeaderSize), 4);
+  int32_t bmpWidth = width;
+  thumbBmp.write(reinterpret_cast<const uint8_t*>(&bmpWidth), 4);
+  int32_t bmpHeight = -height;  // Negative for top-down
+  thumbBmp.write(reinterpret_cast<const uint8_t*>(&bmpHeight), 4);
+  uint16_t planes = 1;
+  thumbBmp.write(reinterpret_cast<const uint8_t*>(&planes), 2);
+  uint16_t bitsPerPixel = 1;
+  thumbBmp.write(reinterpret_cast<const uint8_t*>(&bitsPerPixel), 2);
+  uint32_t compression = 0;
+  thumbBmp.write(reinterpret_cast<const uint8_t*>(&compression), 4);
+  thumbBmp.write(reinterpret_cast<const uint8_t*>(&imageSize), 4);
+  int32_t ppmX = 2835;  // 72 DPI
+  thumbBmp.write(reinterpret_cast<const uint8_t*>(&ppmX), 4);
+  int32_t ppmY = 2835;
+  thumbBmp.write(reinterpret_cast<const uint8_t*>(&ppmY), 4);
+  uint32_t colorsUsed = 2;
+  thumbBmp.write(reinterpret_cast<const uint8_t*>(&colorsUsed), 4);
+  uint32_t colorsImportant = 2;
+  thumbBmp.write(reinterpret_cast<const uint8_t*>(&colorsImportant), 4);
+
+  // Color palette (2 colors for 1-bit)
+  uint8_t black[4] = {0x00, 0x00, 0x00, 0x00};  // Color 0: Black
+  thumbBmp.write(black, 4);
+  uint8_t white[4] = {0xFF, 0xFF, 0xFF, 0x00};  // Color 1: White
+  thumbBmp.write(white, 4);
+
+  // Generate X pattern bitmap data
+  // In BMP, 0 = black (first color in palette), 1 = white
+  // We'll draw black pixels on white background
+  for (int y = 0; y < height; y++) {
+    std::vector<uint8_t> rowData(rowBytes, 0xFF);  // Initialize to all white (1s)
+
+    // Map this row to a horizontal position for diagonals
+    const int scaledY = (y * width) / height;
+    const int thickness = 2;  // thickness of diagonal lines in pixels
+
+    for (int x = 0; x < width; x++) {
+      bool drawPixel = false;
+      // Main diagonal (top-left to bottom-right)
+      if (std::abs(x - scaledY) <= thickness) drawPixel = true;
+      // Other diagonal (top-right to bottom-left)
+      if (std::abs(x - (width - 1 - scaledY)) <= thickness) drawPixel = true;
+
+      if (drawPixel) {
+        const int byteIndex = x / 8;
+        const int bitIndex = 7 - (x % 8);  // MSB first
+        rowData[byteIndex] &= static_cast<uint8_t>(~(1 << bitIndex));
+      }
+    }
+
+    // Write the row data
+    thumbBmp.write(rowData.data(), rowBytes);
+  }
+
+  thumbBmp.close();
+  LOG_DBG("EBP", "Generated invalid format thumbnail BMP");
+  return true;
+}
+
+bool Epub::generateInvalidFormatCoverBmp(bool cropped) const {
+  // Create a simple 1-bit BMP with an X pattern to indicate invalid format.
+  // This BMP is intentionally a valid image that visually indicates a
+  // malformed/unsupported cover image instead of leaving an empty marker
+  // file that would cause repeated generation attempts.
+  // Derive logical portrait dimensions from the display hardware constants
+  // EInkDisplay reports native panel orientation as 800x480; use min/max
+  const int hwW = HalDisplay::DISPLAY_WIDTH;
+  const int hwH = HalDisplay::DISPLAY_HEIGHT;
+  const int width = std::min(hwW, hwH);          // logical portrait width (480)
+  const int height = std::max(hwW, hwH);         // logical portrait height (800)
+  const int rowBytes = ((width + 31) / 32) * 4;  // 1-bit rows padded to 4-byte boundary
+  const int imageSize = rowBytes * height;
+  const int fileSize = 14 + 40 + 8 + imageSize;  // Header + DIB + palette + data
+  const int dataOffset = 14 + 40 + 8;
+
+  FsFile coverBmp;
+  if (!Storage.openFileForWrite("EBP", getCoverBmpPath(cropped), coverBmp)) {
+    return false;
+  }
+
+  // BMP file header (14 bytes)
+  coverBmp.write('B');
+  coverBmp.write('M');
+  coverBmp.write(reinterpret_cast<const uint8_t*>(&fileSize), 4);
+  uint32_t reserved = 0;
+  coverBmp.write(reinterpret_cast<const uint8_t*>(&reserved), 4);
+  coverBmp.write(reinterpret_cast<const uint8_t*>(&dataOffset), 4);
+
+  // DIB header (BITMAPINFOHEADER - 40 bytes)
+  uint32_t dibHeaderSize = 40;
+  coverBmp.write(reinterpret_cast<const uint8_t*>(&dibHeaderSize), 4);
+  int32_t bmpWidth = width;
+  coverBmp.write(reinterpret_cast<const uint8_t*>(&bmpWidth), 4);
+  int32_t bmpHeight = -height;  // Negative for top-down
+  coverBmp.write(reinterpret_cast<const uint8_t*>(&bmpHeight), 4);
+  uint16_t planes = 1;
+  coverBmp.write(reinterpret_cast<const uint8_t*>(&planes), 2);
+  uint16_t bitsPerPixel = 1;
+  coverBmp.write(reinterpret_cast<const uint8_t*>(&bitsPerPixel), 2);
+  uint32_t compression = 0;
+  coverBmp.write(reinterpret_cast<const uint8_t*>(&compression), 4);
+  coverBmp.write(reinterpret_cast<const uint8_t*>(&imageSize), 4);
+  int32_t ppmX = 2835;  // 72 DPI
+  coverBmp.write(reinterpret_cast<const uint8_t*>(&ppmX), 4);
+  int32_t ppmY = 2835;
+  coverBmp.write(reinterpret_cast<const uint8_t*>(&ppmY), 4);
+  uint32_t colorsUsed = 2;
+  coverBmp.write(reinterpret_cast<const uint8_t*>(&colorsUsed), 4);
+  uint32_t colorsImportant = 2;
+  coverBmp.write(reinterpret_cast<const uint8_t*>(&colorsImportant), 4);
+
+  // Color palette (2 colors for 1-bit)
+  uint8_t black[4] = {0x00, 0x00, 0x00, 0x00};  // Color 0: Black
+  coverBmp.write(black, 4);
+  uint8_t white[4] = {0xFF, 0xFF, 0xFF, 0x00};  // Color 1: White
+  coverBmp.write(white, 4);
+
+  // Generate X pattern bitmap data
+  // In BMP, 0 = black (first color in palette), 1 = white
+  // We'll draw black pixels on white background
+  for (int y = 0; y < height; y++) {
+    std::vector<uint8_t> rowData(rowBytes, 0xFF);  // Initialize to all white (1s)
+
+    const int scaledY = (y * width) / height;
+    const int thickness = 6;  // thicker lines for full-cover visibility
+
+    for (int x = 0; x < width; x++) {
+      bool drawPixel = false;
+      if (std::abs(x - scaledY) <= thickness) drawPixel = true;
+      if (std::abs(x - (width - 1 - scaledY)) <= thickness) drawPixel = true;
+
+      if (drawPixel) {
+        const int byteIndex = x / 8;
+        const int bitIndex = 7 - (x % 8);
+        rowData[byteIndex] &= static_cast<uint8_t>(~(1 << bitIndex));
+      }
+    }
+
+    coverBmp.write(rowData.data(), rowBytes);
+  }
+
+  coverBmp.close();
+  LOG_DBG("EBP", "Generated invalid format cover BMP");
+  return true;
+}
+
 uint8_t* Epub::readItemContentsToBytes(const std::string& itemHref, size_t* size, const bool trailingNullByte) const {
   if (itemHref.empty()) {
     LOG_DBG("EBP", "Failed to read item, empty href");
@@ -724,3 +938,45 @@ float Epub::calculateProgress(const int currentSpineIndex, const float currentSp
   const float totalProgress = static_cast<float>(prevChapterSize) + sectionProgSize;
   return totalProgress / static_cast<float>(bookSize);
 }
+
+bool Epub::isValidThumbnailBmp(const std::string& bmpPath) {
+  if (!Storage.exists(bmpPath.c_str())) {
+    return false;
+  }
+  FsFile file = Storage.open(bmpPath.c_str());
+  if (!file) {
+    LOG_ERR("EBP", "Failed to open thumbnail BMP at path: %s", bmpPath.c_str());
+    return false;
+  }
+  size_t fileSize = file.size();
+  if (fileSize == 0) {
+    // Empty file is a marker for "no cover available"
+    LOG_DBG("EBP", "Thumbnail BMP is empty (no cover marker) at path: %s", bmpPath.c_str());
+    file.close();
+    return false;
+  }
+  // BMP header starts with 'B' 'M'
+  uint8_t header[2];
+  size_t bytesRead = file.read(header, 2);
+  if (bytesRead != 2) {
+    LOG_ERR("EBP", "Failed to read thumbnail BMP header at path: %s", bmpPath.c_str());
+    file.close();
+    return false;
+  }
+  LOG_DBG("EBP", "Thumbnail BMP header: %c%c", header[0], header[1]);
+  file.close();
+  return header[0] == 'B' && header[1] == 'M';
+}
+
+std::vector<std::string> Epub::getCoverCandidates() const {
+  std::vector<std::string> coverDirectories = {".", "images", "Images", "OEBPS", "OEBPS/images", "OEBPS/Images"};
+  std::vector<std::string> coverExtensions = {".jpg", ".jpeg"};  // add ".png" when PNG cover support is implemented
+  std::vector<std::string> coverCandidates;
+  for (const auto& ext : coverExtensions) {
+    for (const auto& dir : coverDirectories) {
+      std::string candidate = (dir == ".") ? "cover" + ext : dir + "/cover" + ext;
+      coverCandidates.push_back(candidate);
+    }
+  }
+  return coverCandidates;
+}

lib/Epub/Epub.h

@@ -35,8 +35,6 @@ class Epub {
   bool parseTocNcxFile() const;
   bool parseTocNavFile() const;
   void parseCssFiles() const;
-  std::string getCssRulesCache() const;
-  bool loadCssRulesFromCache() const;
 
  public:
   explicit Epub(std::string filepath, const std::string& cacheDir) : filepath(std::move(filepath)) {
@@ -54,10 +52,23 @@ class Epub {
   const std::string& getAuthor() const;
   const std::string& getLanguage() const;
   std::string getCoverBmpPath(bool cropped = false) const;
+  // Generate a 1-bit BMP cover image from the EPUB cover image.
+  // Returns true on success. On conversion failure, callers may use
+  // `generateInvalidFormatCoverBmp` to create a valid marker BMP.
   bool generateCoverBmp(bool cropped = false) const;
+  // Create a valid 1-bit BMP that visually indicates an invalid/unsupported
+  // cover format (an X pattern). This prevents repeated generation attempts
+  // by providing a valid BMP file that `isValidThumbnailBmp` accepts.
+  bool generateInvalidFormatCoverBmp(bool cropped = false) const;
   std::string getThumbBmpPath() const;
   std::string getThumbBmpPath(int height) const;
+  // Generate a thumbnail BMP at the requested `height`. Returns true on
+  // successful conversion. If conversion fails, `generateInvalidFormatThumbBmp`
+  // can be used to write a valid marker image that prevents retries.
   bool generateThumbBmp(int height) const;
+  // Create a valid 1-bit thumbnail BMP with an X marker indicating an
+  // invalid/unsupported cover image instead of leaving an empty marker file.
+  bool generateInvalidFormatThumbBmp(int height) const;
   uint8_t* readItemContentsToBytes(const std::string& itemHref, size_t* size = nullptr,
                                    bool trailingNullByte = false) const;
   bool readItemContentsToStream(const std::string& itemHref, Print& out, size_t chunkSize) const;
@@ -73,5 +84,10 @@ class Epub {
 
   size_t getBookSize() const;
   float calculateProgress(int currentSpineIndex, float currentSpineRead) const;
-  const CssParser* getCssParser() const { return cssParser.get(); }
+  CssParser* getCssParser() const { return cssParser.get(); }
+
+  static bool isValidThumbnailBmp(const std::string& bmpPath);
+
+ private:
+  std::vector<std::string> getCoverCandidates() const;
 };

lib/Epub/Epub/Page.cpp

@@ -1,8 +1,17 @@
 #include "Page.h"
 
+#include <GfxRenderer.h>
 #include <Logging.h>
 #include <Serialization.h>
 
+// Cell padding in pixels (must match TABLE_CELL_PAD_* in ChapterHtmlSlimParser.cpp)
+static constexpr int TABLE_CELL_PADDING_X = 4;
+static constexpr int TABLE_CELL_PADDING_TOP = 1;
+
+// ---------------------------------------------------------------------------
+// PageLine
+// ---------------------------------------------------------------------------
+
 void PageLine::render(GfxRenderer& renderer, const int fontId, const int xOffset, const int yOffset) {
   block->render(renderer, fontId, xPos + xOffset, yPos + yOffset);
 }
@@ -25,6 +34,142 @@ std::unique_ptr<PageLine> PageLine::deserialize(FsFile& file) {
   return std::unique_ptr<PageLine>(new PageLine(std::move(tb), xPos, yPos));
 }
 
+// ---------------------------------------------------------------------------
+// PageImage
+// ---------------------------------------------------------------------------
+
+void PageImage::render(GfxRenderer& renderer, const int fontId, const int xOffset, const int yOffset) {
+  // Images don't use fontId or text rendering
+  imageBlock->render(renderer, xPos + xOffset, yPos + yOffset);
+}
+
+bool PageImage::serialize(FsFile& file) {
+  serialization::writePod(file, xPos);
+  serialization::writePod(file, yPos);
+
+  // serialize ImageBlock
+  return imageBlock->serialize(file);
+}
+
+std::unique_ptr<PageImage> PageImage::deserialize(FsFile& file) {
+  int16_t xPos;
+  int16_t yPos;
+  serialization::readPod(file, xPos);
+  serialization::readPod(file, yPos);
+
+  auto ib = ImageBlock::deserialize(file);
+  return std::unique_ptr<PageImage>(new PageImage(std::move(ib), xPos, yPos));
+}
+
+// ---------------------------------------------------------------------------
+// PageTableRow
+// ---------------------------------------------------------------------------
+
+void PageTableRow::render(GfxRenderer& renderer, const int fontId, const int xOffset, const int yOffset) {
+  const int baseX = xPos + xOffset;
+  const int baseY = yPos + yOffset;
+
+  // Draw horizontal borders (top and bottom of this row)
+  renderer.drawLine(baseX, baseY, baseX + totalWidth, baseY);
+  renderer.drawLine(baseX, baseY + rowHeight, baseX + totalWidth, baseY + rowHeight);
+
+  // Draw vertical borders and render cell contents
+  // Left edge
+  renderer.drawLine(baseX, baseY, baseX, baseY + rowHeight);
+
+  for (const auto& cell : cells) {
+    // Right vertical border for this cell
+    const int cellRightX = baseX + cell.xOffset + cell.columnWidth;
+    renderer.drawLine(cellRightX, baseY, cellRightX, baseY + rowHeight);
+
+    // Render each text line within the cell
+    const int cellTextX = baseX + cell.xOffset + TABLE_CELL_PADDING_X;
+    int cellLineY = baseY + 1 + TABLE_CELL_PADDING_TOP;  // 1px border + top padding
+
+    for (const auto& line : cell.lines) {
+      line->render(renderer, fontId, cellTextX, cellLineY);
+      cellLineY += lineHeight;
+    }
+  }
+}
+
+bool PageTableRow::serialize(FsFile& file) {
+  serialization::writePod(file, xPos);
+  serialization::writePod(file, yPos);
+  serialization::writePod(file, rowHeight);
+  serialization::writePod(file, totalWidth);
+  serialization::writePod(file, lineHeight);
+
+  const uint16_t cellCount = static_cast<uint16_t>(cells.size());
+  serialization::writePod(file, cellCount);
+
+  for (const auto& cell : cells) {
+    serialization::writePod(file, cell.xOffset);
+    serialization::writePod(file, cell.columnWidth);
+
+    const uint16_t lineCount = static_cast<uint16_t>(cell.lines.size());
+    serialization::writePod(file, lineCount);
+
+    for (const auto& line : cell.lines) {
+      if (!line->serialize(file)) {
+        return false;
+      }
+    }
+  }
+
+  return true;
+}
+
+std::unique_ptr<PageTableRow> PageTableRow::deserialize(FsFile& file) {
+  int16_t xPos, yPos, rowHeight, totalWidth, lineHeight;
+  serialization::readPod(file, xPos);
+  serialization::readPod(file, yPos);
+  serialization::readPod(file, rowHeight);
+  serialization::readPod(file, totalWidth);
+  serialization::readPod(file, lineHeight);
+
+  uint16_t cellCount;
+  serialization::readPod(file, cellCount);
+
+  // Sanity check
+  if (cellCount > 100) {
+    LOG_ERR("PTR", "Deserialization failed: cell count %u exceeds maximum", cellCount);
+    return nullptr;
+  }
+
+  std::vector<PageTableCellData> cells;
+  cells.resize(cellCount);
+
+  for (uint16_t c = 0; c < cellCount; ++c) {
+    serialization::readPod(file, cells[c].xOffset);
+    serialization::readPod(file, cells[c].columnWidth);
+
+    uint16_t lineCount;
+    serialization::readPod(file, lineCount);
+
+    if (lineCount > 1000) {
+      LOG_ERR("PTR", "Deserialization failed: line count %u in cell %u exceeds maximum", lineCount, c);
+      return nullptr;
+    }
+
+    cells[c].lines.reserve(lineCount);
+    for (uint16_t l = 0; l < lineCount; ++l) {
+      auto tb = TextBlock::deserialize(file);
+      if (!tb) {
+        return nullptr;
+      }
+      cells[c].lines.push_back(std::move(tb));
+    }
+  }
+
+  return std::unique_ptr<PageTableRow>(
+      new PageTableRow(std::move(cells), rowHeight, totalWidth, lineHeight, xPos, yPos));
+}
+
+// ---------------------------------------------------------------------------
+// Page
+// ---------------------------------------------------------------------------
+
 void Page::render(GfxRenderer& renderer, const int fontId, const int xOffset, const int yOffset) const {
   for (auto& element : elements) {
     element->render(renderer, fontId, xOffset, yOffset);
@@ -36,8 +181,7 @@ bool Page::serialize(FsFile& file) const {
   serialization::writePod(file, count);
 
   for (const auto& el : elements) {
-    // Only PageLine exists currently
-    serialization::writePod(file, static_cast<uint8_t>(TAG_PageLine));
+    serialization::writePod(file, static_cast<uint8_t>(el->getTag()));
     if (!el->serialize(file)) {
       return false;
     }
@@ -59,6 +203,16 @@ std::unique_ptr<Page> Page::deserialize(FsFile& file) {
     if (tag == TAG_PageLine) {
       auto pl = PageLine::deserialize(file);
       page->elements.push_back(std::move(pl));
+    } else if (tag == TAG_PageTableRow) {
+      auto tr = PageTableRow::deserialize(file);
+      if (!tr) {
+        LOG_ERR("PGE", "Deserialization failed for PageTableRow at element %u", i);
+        return nullptr;
+      }
+      page->elements.push_back(std::move(tr));
+    } else if (tag == TAG_PageImage) {
+      auto pi = PageImage::deserialize(file);
+      page->elements.push_back(std::move(pi));
     } else {
       LOG_ERR("PGE", "Deserialization failed: Unknown tag %u", tag);
       return nullptr;
@@ -67,3 +221,50 @@ std::unique_ptr<Page> Page::deserialize(FsFile& file) {
 
   return page;
 }
+
+bool Page::getImageBoundingBox(int& outX, int& outY, int& outWidth, int& outHeight) const {
+  bool firstImage = true;
+  for (const auto& el : elements) {
+    if (el->getTag() == TAG_PageImage) {
+      PageImage* pi = static_cast<PageImage*>(el.get());
+      ImageBlock* ib = pi->getImageBlock();
+
+      if (firstImage) {
+        // Initialize with first image bounds
+        outX = pi->xPos;
+        outY = pi->yPos;
+        outWidth = ib->getWidth();
+        outHeight = ib->getHeight();
+        firstImage = false;
+      } else {
+        // Expand bounding box to include this image
+        int imgX = pi->xPos;
+        int imgY = pi->yPos;
+        int imgW = ib->getWidth();
+        int imgH = ib->getHeight();
+
+        // Expand right boundary
+        if (imgX + imgW > outX + outWidth) {
+          outWidth = (imgX + imgW) - outX;
+        }
+        // Expand left boundary
+        if (imgX < outX) {
+          int oldRight = outX + outWidth;
+          outX = imgX;
+          outWidth = oldRight - outX;
+        }
+        // Expand bottom boundary
+        if (imgY + imgH > outY + outHeight) {
+          outHeight = (imgY + imgH) - outY;
+        }
+        // Expand top boundary
+        if (imgY < outY) {
+          int oldBottom = outY + outHeight;
+          outY = imgY;
+          outHeight = oldBottom - outY;
+        }
+      }
+    }
+  }
+  return !firstImage;  // Return true if at least one image was found
+}

lib/Epub/Epub/Page.h

@@ -1,13 +1,17 @@
 #pragma once
 #include <HalStorage.h>
 
+#include <algorithm>
 #include <utility>
 #include <vector>
 
+#include "blocks/ImageBlock.h"
 #include "blocks/TextBlock.h"
 
 enum PageElementTag : uint8_t {
   TAG_PageLine = 1,
+  TAG_PageTableRow = 2,
+  TAG_PageImage = 3,
 };
 
 // represents something that has been added to a page
@@ -17,6 +21,7 @@ class PageElement {
   int16_t yPos;
   explicit PageElement(const int16_t xPos, const int16_t yPos) : xPos(xPos), yPos(yPos) {}
   virtual ~PageElement() = default;
+  virtual PageElementTag getTag() const = 0;
   virtual void render(GfxRenderer& renderer, int fontId, int xOffset, int yOffset) = 0;
   virtual bool serialize(FsFile& file) = 0;
 };
@@ -29,11 +34,58 @@ class PageLine final : public PageElement {
   PageLine(std::shared_ptr<TextBlock> block, const int16_t xPos, const int16_t yPos)
       : PageElement(xPos, yPos), block(std::move(block)) {}
   const std::shared_ptr<TextBlock>& getBlock() const { return block; }
+  PageElementTag getTag() const override { return TAG_PageLine; }
   void render(GfxRenderer& renderer, int fontId, int xOffset, int yOffset) override;
   bool serialize(FsFile& file) override;
   static std::unique_ptr<PageLine> deserialize(FsFile& file);
 };
 
+/// Data for a single cell within a PageTableRow.
+struct PageTableCellData {
+  std::vector<std::shared_ptr<TextBlock>> lines;  // Laid-out text lines for this cell
+  uint16_t columnWidth = 0;                        // Width of this column in pixels
+  uint16_t xOffset = 0;                            // X offset of this cell within the row
+};
+
+/// A table row element that renders cells in a column-aligned grid with borders.
+class PageTableRow final : public PageElement {
+  std::vector<PageTableCellData> cells;
+  int16_t rowHeight;   // Total row height in pixels
+  int16_t totalWidth;  // Total table width in pixels
+  int16_t lineHeight;  // Height of one text line (for vertical positioning of cell lines)
+
+ public:
+  PageTableRow(std::vector<PageTableCellData> cells, int16_t rowHeight, int16_t totalWidth, int16_t lineHeight,
+               int16_t xPos, int16_t yPos)
+      : PageElement(xPos, yPos),
+        cells(std::move(cells)),
+        rowHeight(rowHeight),
+        totalWidth(totalWidth),
+        lineHeight(lineHeight) {}
+
+  int16_t getHeight() const { return rowHeight; }
+  PageElementTag getTag() const override { return TAG_PageTableRow; }
+  void render(GfxRenderer& renderer, int fontId, int xOffset, int yOffset) override;
+  bool serialize(FsFile& file) override;
+  static std::unique_ptr<PageTableRow> deserialize(FsFile& file);
+};
+
+// An image element on a page
+class PageImage final : public PageElement {
+  std::shared_ptr<ImageBlock> imageBlock;
+
+ public:
+  PageImage(std::shared_ptr<ImageBlock> block, const int16_t xPos, const int16_t yPos)
+      : PageElement(xPos, yPos), imageBlock(std::move(block)) {}
+  void render(GfxRenderer& renderer, int fontId, int xOffset, int yOffset) override;
+  bool serialize(FsFile& file) override;
+  PageElementTag getTag() const override { return TAG_PageImage; }
+  static std::unique_ptr<PageImage> deserialize(FsFile& file);
+
+  // Helper to get image block dimensions (needed for bounding box calculation)
+  ImageBlock* getImageBlock() const { return imageBlock.get(); }
+};
+
 class Page {
  public:
   // the list of block index and line numbers on this page
@@ -41,4 +93,15 @@ class Page {
   void render(GfxRenderer& renderer, int fontId, int xOffset, int yOffset) const;
   bool serialize(FsFile& file) const;
   static std::unique_ptr<Page> deserialize(FsFile& file);
+
+  // Check if page contains any images (used to force full refresh)
+  bool hasImages() const {
+    return std::any_of(elements.begin(), elements.end(),
+                       [](const std::shared_ptr<PageElement>& el) { return el->getTag() == TAG_PageImage; });
+  }
+
+  // Get the bounding box of all images on this page.
+  // Returns true if page has images and fills out the bounding box coordinates.
+  // If no images, returns false.
+  bool getImageBoundingBox(int& outX, int& outY, int& outWidth, int& outHeight) const;
 };

lib/Epub/Epub/ParsedText.cpp

@@ -62,6 +62,13 @@ void ParsedText::addWord(std::string word, const EpdFontFamily::Style fontStyle,
   }
   wordStyles.push_back(combinedStyle);
   wordContinues.push_back(attachToPrevious);
+  forceBreakAfter.push_back(false);
+}
+
+void ParsedText::addLineBreak() {
+  if (!words.empty()) {
+    forceBreakAfter.back() = true;
+  }
 }
 
 // Consumes data to minimize memory usage
@@ -148,6 +155,11 @@ std::vector<size_t> ParsedText::computeLineBreaks(const GfxRenderer& renderer, c
     const int effectivePageWidth = i == 0 ? pageWidth - firstLineIndent : pageWidth;
 
     for (size_t j = i; j < totalWordCount; ++j) {
+      // If the previous word has a forced line break, this line cannot include word j
+      if (j > static_cast<size_t>(i) && !forceBreakAfter.empty() && forceBreakAfter[j - 1]) {
+        break;
+      }
+
       // Add space before word j, unless it's the first word on the line or a continuation
       const int gap = j > static_cast<size_t>(i) && !continuesVec[j] ? spaceWidth : 0;
       currlen += wordWidths[j] + gap;
@@ -156,8 +168,11 @@ std::vector<size_t> ParsedText::computeLineBreaks(const GfxRenderer& renderer, c
         break;
       }
 
-      // Cannot break after word j if the next word attaches to it (continuation group)
-      if (j + 1 < totalWordCount && continuesVec[j + 1]) {
+      // Forced line break after word j overrides continuation (must end line here)
+      const bool mustBreakHere = !forceBreakAfter.empty() && forceBreakAfter[j];
+
+      // Cannot break after word j if the next word attaches to it (unless forced)
+      if (!mustBreakHere && j + 1 < totalWordCount && continuesVec[j + 1]) {
         continue;
       }
 
@@ -180,6 +195,11 @@ std::vector<size_t> ParsedText::computeLineBreaks(const GfxRenderer& renderer, c
         dp[i] = cost;
         ans[i] = j;  // j is the index of the last word in this optimal line
       }
+
+      // After evaluating cost, enforce forced break - no more words on this line
+      if (mustBreakHere) {
+        break;
+      }
     }
 
     // Handle oversized word: if no valid configuration found, force single-word line
@@ -254,6 +274,11 @@ std::vector<size_t> ParsedText::computeHyphenatedLineBreaks(const GfxRenderer& r
 
     // Consume as many words as possible for current line, splitting when prefixes fit
     while (currentIndex < wordWidths.size()) {
+      // If the previous word has a forced line break, stop - this word starts a new line
+      if (currentIndex > lineStart && !forceBreakAfter.empty() && forceBreakAfter[currentIndex - 1]) {
+        break;
+      }
+
       const bool isFirstWord = currentIndex == lineStart;
       const int spacing = isFirstWord || continuesVec[currentIndex] ? 0 : spaceWidth;
       const int candidateWidth = spacing + wordWidths[currentIndex];
@@ -262,6 +287,11 @@ std::vector<size_t> ParsedText::computeHyphenatedLineBreaks(const GfxRenderer& r
       if (lineWidth + candidateWidth <= effectivePageWidth) {
         lineWidth += candidateWidth;
         ++currentIndex;
+
+        // If the word we just added has a forced break, end this line now
+        if (!forceBreakAfter.empty() && forceBreakAfter[currentIndex - 1]) {
+          break;
+        }
         continue;
       }
 
@@ -287,7 +317,12 @@ std::vector<size_t> ParsedText::computeHyphenatedLineBreaks(const GfxRenderer& r
 
     // Don't break before a continuation word (e.g., orphaned "?" after "question").
     // Backtrack to the start of the continuation group so the whole group moves to the next line.
+    // But don't backtrack past a forced break point.
     while (currentIndex > lineStart + 1 && currentIndex < wordWidths.size() && continuesVec[currentIndex]) {
+      // Don't backtrack past a forced break
+      if (!forceBreakAfter.empty() && forceBreakAfter[currentIndex - 1]) {
+        break;
+      }
       --currentIndex;
     }
 
@@ -361,6 +396,13 @@ bool ParsedText::hyphenateWordAtIndex(const size_t wordIndex, const int availabl
   wordContinues[wordIndex] = false;
   wordContinues.insert(wordContinues.begin() + wordIndex + 1, originalContinuedToNext);
 
+  // Forced break belongs to the original whole word; transfer it to the remainder (last part).
+  if (!forceBreakAfter.empty()) {
+    const bool originalForceBreak = forceBreakAfter[wordIndex];
+    forceBreakAfter[wordIndex] = false;  // prefix doesn't force break
+    forceBreakAfter.insert(forceBreakAfter.begin() + wordIndex + 1, originalForceBreak);
+  }
+
   // Update cached widths to reflect the new prefix/remainder pairing.
   wordWidths[wordIndex] = static_cast<uint16_t>(chosenWidth);
   const uint16_t remainderWidth = measureWordWidth(renderer, fontId, remainder, style);
@@ -447,3 +489,22 @@ void ParsedText::extractLine(const size_t breakIndex, const int pageWidth, const
   processLine(
       std::make_shared<TextBlock>(std::move(lineWords), std::move(lineXPos), std::move(lineWordStyles), blockStyle));
 }
+
+uint16_t ParsedText::getNaturalWidth(const GfxRenderer& renderer, const int fontId) const {
+  if (words.empty()) {
+    return 0;
+  }
+
+  const int spaceWidth = renderer.getSpaceWidth(fontId);
+  int totalWidth = 0;
+
+  for (size_t i = 0; i < words.size(); ++i) {
+    totalWidth += measureWordWidth(renderer, fontId, words[i], wordStyles[i]);
+    // Add a space before this word unless it's the first word or a continuation
+    if (i > 0 && !wordContinues[i]) {
+      totalWidth += spaceWidth;
+    }
+  }
+
+  return static_cast<uint16_t>(std::min(totalWidth, static_cast<int>(UINT16_MAX)));
+}

lib/Epub/Epub/ParsedText.h

@@ -15,7 +15,8 @@ class GfxRenderer;
 class ParsedText {
   std::vector<std::string> words;
   std::vector<EpdFontFamily::Style> wordStyles;
-  std::vector<bool> wordContinues;  // true = word attaches to previous (no space before it)
+  std::vector<bool> wordContinues;    // true = word attaches to previous (no space before it)
+  std::vector<bool> forceBreakAfter;  // true = mandatory line break after this word (e.g. <br> in table cells)
   BlockStyle blockStyle;
   bool extraParagraphSpacing;
   bool hyphenationEnabled;
@@ -40,6 +41,10 @@ class ParsedText {
   ~ParsedText() = default;
 
   void addWord(std::string word, EpdFontFamily::Style fontStyle, bool underline = false, bool attachToPrevious = false);
+
+  /// Mark a forced line break after the last word (e.g. for <br> within table cells).
+  /// If no words have been added yet, this is a no-op.
+  void addLineBreak();
   void setBlockStyle(const BlockStyle& blockStyle) { this->blockStyle = blockStyle; }
   BlockStyle& getBlockStyle() { return blockStyle; }
   size_t size() const { return words.size(); }
@@ -47,4 +52,9 @@ class ParsedText {
   void layoutAndExtractLines(const GfxRenderer& renderer, int fontId, uint16_t viewportWidth,
                              const std::function<void(std::shared_ptr<TextBlock>)>& processLine,
                              bool includeLastLine = true);
+
+  /// Returns the "natural" width of the content if it were laid out on a single line
+  /// (sum of word widths + space widths between non-continuation words).
+  /// Used by table layout to determine column widths before line-breaking.
+  uint16_t getNaturalWidth(const GfxRenderer& renderer, int fontId) const;
 };

lib/Epub/Epub/Section.cpp

@@ -9,7 +9,7 @@
 #include "parsers/ChapterHtmlSlimParser.h"
 
 namespace {
-constexpr uint8_t SECTION_FILE_VERSION = 12;
+constexpr uint8_t SECTION_FILE_VERSION = 13;
 constexpr uint32_t HEADER_SIZE = sizeof(uint8_t) + sizeof(int) + sizeof(float) + sizeof(bool) + sizeof(uint8_t) +
                                  sizeof(uint16_t) + sizeof(uint16_t) + sizeof(uint16_t) + sizeof(bool) + sizeof(bool) +
                                  sizeof(uint32_t);
@@ -181,11 +181,25 @@ bool Section::createSectionFile(const int fontId, const float lineCompression, c
                          viewportHeight, hyphenationEnabled, embeddedStyle);
   std::vector<uint32_t> lut = {};
 
+  // Derive the content base directory and image cache path prefix for the parser
+  size_t lastSlash = localPath.find_last_of('/');
+  std::string contentBase = (lastSlash != std::string::npos) ? localPath.substr(0, lastSlash + 1) : "";
+  std::string imageBasePath = epub->getCachePath() + "/img_" + std::to_string(spineIndex) + "_";
+
+  CssParser* cssParser = nullptr;
+  if (embeddedStyle) {
+    cssParser = epub->getCssParser();
+    if (cssParser) {
+      if (!cssParser->loadFromCache()) {
+        LOG_ERR("SCT", "Failed to load CSS from cache");
+      }
+    }
+  }
   ChapterHtmlSlimParser visitor(
-      tmpHtmlPath, renderer, fontId, lineCompression, extraParagraphSpacing, paragraphAlignment, viewportWidth,
+      epub, tmpHtmlPath, renderer, fontId, lineCompression, extraParagraphSpacing, paragraphAlignment, viewportWidth,
       viewportHeight, hyphenationEnabled,
       [this, &lut](std::unique_ptr<Page> page) { lut.emplace_back(this->onPageComplete(std::move(page))); },
-      embeddedStyle, popupFn, embeddedStyle ? epub->getCssParser() : nullptr);
+      embeddedStyle, contentBase, imageBasePath, popupFn, cssParser);
   Hyphenator::setPreferredLanguage(epub->getLanguage());
   success = visitor.parseAndBuildPages();
 
@@ -194,6 +208,9 @@ bool Section::createSectionFile(const int fontId, const float lineCompression, c
     LOG_ERR("SCT", "Failed to parse XML and build pages");
     file.close();
     Storage.remove(filePath.c_str());
+    if (cssParser) {
+      cssParser->clear();
+    }
     return false;
   }
 
@@ -220,6 +237,9 @@ bool Section::createSectionFile(const int fontId, const float lineCompression, c
   serialization::writePod(file, pageCount);
   serialization::writePod(file, lutOffset);
   file.close();
+  if (cssParser) {
+    cssParser->clear();
+  }
   return true;
 }
 

lib/Epub/Epub/TableData.h

@@ -0,0 +1,29 @@
+#pragma once
+
+#include <memory>
+#include <vector>
+
+#include "ParsedText.h"
+#include "css/CssStyle.h"
+
+/// A single cell in a table row.
+struct TableCell {
+  std::unique_ptr<ParsedText> content;
+  bool isHeader = false;   // true for <th>, false for <td>
+  int colspan = 1;          // number of logical columns this cell spans
+  CssLength widthHint;      // width hint from HTML attribute or CSS (if hasWidthHint)
+  bool hasWidthHint = false;
+};
+
+/// A single row in a table.
+struct TableRow {
+  std::vector<TableCell> cells;
+};
+
+/// Buffered table data collected during SAX parsing.
+/// The entire table must be buffered before layout because column widths
+/// depend on content across all rows.
+struct TableData {
+  std::vector<TableRow> rows;
+  std::vector<CssLength> colWidthHints;  // width hints from <col> tags, indexed by logical column
+};

lib/Epub/Epub/blocks/Block.h

@@ -8,7 +8,7 @@ typedef enum { TEXT_BLOCK, IMAGE_BLOCK } BlockType;
 class Block {
  public:
   virtual ~Block() = default;
-  virtual void layout(GfxRenderer& renderer) = 0;
+
   virtual BlockType getType() = 0;
   virtual bool isEmpty() = 0;
   virtual void finish() {}

lib/Epub/Epub/blocks/ImageBlock.cpp

@@ -0,0 +1,175 @@
+#include "ImageBlock.h"
+
+#include <FsHelpers.h>
+#include <GfxRenderer.h>
+#include <HardwareSerial.h>
+#include <SDCardManager.h>
+#include <Serialization.h>
+
+#include "../converters/DitherUtils.h"
+#include "../converters/ImageDecoderFactory.h"
+
+// Cache file format:
+// - uint16_t width
+// - uint16_t height
+// - uint8_t pixels[...] - 2 bits per pixel, packed (4 pixels per byte), row-major order
+
+ImageBlock::ImageBlock(const std::string& imagePath, int16_t width, int16_t height)
+    : imagePath(imagePath), width(width), height(height) {}
+
+bool ImageBlock::imageExists() const { return Storage.exists(imagePath.c_str()); }
+
+namespace {
+
+std::string getCachePath(const std::string& imagePath) {
+  // Replace extension with .pxc (pixel cache)
+  size_t dotPos = imagePath.rfind('.');
+  if (dotPos != std::string::npos) {
+    return imagePath.substr(0, dotPos) + ".pxc";
+  }
+  return imagePath + ".pxc";
+}
+
+bool renderFromCache(GfxRenderer& renderer, const std::string& cachePath, int x, int y, int expectedWidth,
+                     int expectedHeight) {
+  FsFile cacheFile;
+  if (!Storage.openFileForRead("IMG", cachePath, cacheFile)) {
+    return false;
+  }
+
+  uint16_t cachedWidth, cachedHeight;
+  if (cacheFile.read(&cachedWidth, 2) != 2 || cacheFile.read(&cachedHeight, 2) != 2) {
+    cacheFile.close();
+    return false;
+  }
+
+  // Verify dimensions are close (allow 1 pixel tolerance for rounding differences)
+  int widthDiff = abs(cachedWidth - expectedWidth);
+  int heightDiff = abs(cachedHeight - expectedHeight);
+  if (widthDiff > 1 || heightDiff > 1) {
+    Serial.printf("[%lu] [IMG] Cache dimension mismatch: %dx%d vs %dx%d\n", millis(), cachedWidth, cachedHeight,
+                  expectedWidth, expectedHeight);
+    cacheFile.close();
+    return false;
+  }
+
+  // Use cached dimensions for rendering (they're the actual decoded size)
+  expectedWidth = cachedWidth;
+  expectedHeight = cachedHeight;
+
+  Serial.printf("[%lu] [IMG] Loading from cache: %s (%dx%d)\n", millis(), cachePath.c_str(), cachedWidth, cachedHeight);
+
+  // Read and render row by row to minimize memory usage
+  const int bytesPerRow = (cachedWidth + 3) / 4;  // 2 bits per pixel, 4 pixels per byte
+  uint8_t* rowBuffer = (uint8_t*)malloc(bytesPerRow);
+  if (!rowBuffer) {
+    Serial.printf("[%lu] [IMG] Failed to allocate row buffer\n", millis());
+    cacheFile.close();
+    return false;
+  }
+
+  for (int row = 0; row < cachedHeight; row++) {
+    if (cacheFile.read(rowBuffer, bytesPerRow) != bytesPerRow) {
+      Serial.printf("[%lu] [IMG] Cache read error at row %d\n", millis(), row);
+      free(rowBuffer);
+      cacheFile.close();
+      return false;
+    }
+
+    int destY = y + row;
+    for (int col = 0; col < cachedWidth; col++) {
+      int byteIdx = col / 4;
+      int bitShift = 6 - (col % 4) * 2;  // MSB first within byte
+      uint8_t pixelValue = (rowBuffer[byteIdx] >> bitShift) & 0x03;
+
+      drawPixelWithRenderMode(renderer, x + col, destY, pixelValue);
+    }
+  }
+
+  free(rowBuffer);
+  cacheFile.close();
+  Serial.printf("[%lu] [IMG] Cache render complete\n", millis());
+  return true;
+}
+
+}  // namespace
+
+void ImageBlock::render(GfxRenderer& renderer, const int x, const int y) {
+  Serial.printf("[%lu] [IMG] Rendering image at %d,%d: %s (%dx%d)\n", millis(), x, y, imagePath.c_str(), width, height);
+
+  const int screenWidth = renderer.getScreenWidth();
+  const int screenHeight = renderer.getScreenHeight();
+
+  // Bounds check render position using logical screen dimensions
+  if (x < 0 || y < 0 || x + width > screenWidth || y + height > screenHeight) {
+    Serial.printf("[%lu] [IMG] Invalid render position: (%d,%d) size (%dx%d) screen (%dx%d)\n", millis(), x, y, width,
+                  height, screenWidth, screenHeight);
+    return;
+  }
+
+  // Try to render from cache first
+  std::string cachePath = getCachePath(imagePath);
+  if (renderFromCache(renderer, cachePath, x, y, width, height)) {
+    return;  // Successfully rendered from cache
+  }
+
+  // No cache - need to decode the image
+  // Check if image file exists
+  FsFile file;
+  if (!Storage.openFileForRead("IMG", imagePath, file)) {
+    Serial.printf("[%lu] [IMG] Image file not found: %s\n", millis(), imagePath.c_str());
+    return;
+  }
+  size_t fileSize = file.size();
+  file.close();
+
+  if (fileSize == 0) {
+    Serial.printf("[%lu] [IMG] Image file is empty: %s\n", millis(), imagePath.c_str());
+    return;
+  }
+
+  Serial.printf("[%lu] [IMG] Decoding and caching: %s\n", millis(), imagePath.c_str());
+
+  RenderConfig config;
+  config.x = x;
+  config.y = y;
+  config.maxWidth = width;
+  config.maxHeight = height;
+  config.useGrayscale = true;
+  config.useDithering = true;
+  config.performanceMode = false;
+  config.useExactDimensions = true;  // Use pre-calculated dimensions to avoid rounding mismatches
+  config.cachePath = cachePath;      // Enable caching during decode
+
+  ImageToFramebufferDecoder* decoder = ImageDecoderFactory::getDecoder(imagePath);
+  if (!decoder) {
+    Serial.printf("[%lu] [IMG] No decoder found for image: %s\n", millis(), imagePath.c_str());
+    return;
+  }
+
+  Serial.printf("[%lu] [IMG] Using %s decoder\n", millis(), decoder->getFormatName());
+
+  bool success = decoder->decodeToFramebuffer(imagePath, renderer, config);
+  if (!success) {
+    Serial.printf("[%lu] [IMG] Failed to decode image: %s\n", millis(), imagePath.c_str());
+    return;
+  }
+
+  Serial.printf("[%lu] [IMG] Decode successful\n", millis());
+}
+
+bool ImageBlock::serialize(FsFile& file) {
+  serialization::writeString(file, imagePath);
+  serialization::writePod(file, width);
+  serialization::writePod(file, height);
+  return true;
+}
+
+std::unique_ptr<ImageBlock> ImageBlock::deserialize(FsFile& file) {
+  std::string path;
+  serialization::readString(file, path);
+  int16_t w, h;
+  serialization::readPod(file, w);
+  serialization::readPod(file, h);
+  return std::unique_ptr<ImageBlock>(new ImageBlock(path, w, h));
+}

lib/Epub/Epub/blocks/ImageBlock.h

@@ -0,0 +1,31 @@
+#pragma once
+#include <SdFat.h>
+
+#include <memory>
+#include <string>
+
+#include "Block.h"
+
+class ImageBlock final : public Block {
+ public:
+  ImageBlock(const std::string& imagePath, int16_t width, int16_t height);
+  ~ImageBlock() override = default;
+
+  const std::string& getImagePath() const { return imagePath; }
+  int16_t getWidth() const { return width; }
+  int16_t getHeight() const { return height; }
+
+  bool imageExists() const;
+
+  BlockType getType() override { return IMAGE_BLOCK; }
+  bool isEmpty() override { return false; }
+
+  void render(GfxRenderer& renderer, const int x, const int y);
+  bool serialize(FsFile& file);
+  static std::unique_ptr<ImageBlock> deserialize(FsFile& file);
+
+ private:
+  std::string imagePath;
+  int16_t width;
+  int16_t height;
+};

lib/Epub/Epub/blocks/TextBlock.h

@@ -31,7 +31,6 @@ class TextBlock final : public Block {
   const std::vector<uint16_t>& getWordXpos() const { return wordXpos; }
   const std::vector<EpdFontFamily::Style>& getWordStyles() const { return wordStyles; }
   bool isEmpty() override { return words.empty(); }
-  void layout(GfxRenderer& renderer) override {};
   // given a renderer works out where to break the words into lines
   void render(const GfxRenderer& renderer, int fontId, int x, int y) const;
   BlockType getType() override { return TEXT_BLOCK; }

lib/Epub/Epub/converters/DitherUtils.h

@@ -0,0 +1,40 @@
+#pragma once
+
+#include <GfxRenderer.h>
+#include <stdint.h>
+
+// 4x4 Bayer matrix for ordered dithering
+inline const uint8_t bayer4x4[4][4] = {
+    {0, 8, 2, 10},
+    {12, 4, 14, 6},
+    {3, 11, 1, 9},
+    {15, 7, 13, 5},
+};
+
+// Apply Bayer dithering and quantize to 4 levels (0-3)
+// Stateless - works correctly with any pixel processing order
+inline uint8_t applyBayerDither4Level(uint8_t gray, int x, int y) {
+  int bayer = bayer4x4[y & 3][x & 3];
+  int dither = (bayer - 8) * 5;  // Scale to +/-40 (half of quantization step 85)
+
+  int adjusted = gray + dither;
+  if (adjusted < 0) adjusted = 0;
+  if (adjusted > 255) adjusted = 255;
+
+  if (adjusted < 64) return 0;
+  if (adjusted < 128) return 1;
+  if (adjusted < 192) return 2;
+  return 3;
+}
+
+// Draw a pixel respecting the current render mode for grayscale support
+inline void drawPixelWithRenderMode(GfxRenderer& renderer, int x, int y, uint8_t pixelValue) {
+  GfxRenderer::RenderMode renderMode = renderer.getRenderMode();
+  if (renderMode == GfxRenderer::BW && pixelValue < 3) {
+    renderer.drawPixel(x, y, true);
+  } else if (renderMode == GfxRenderer::GRAYSCALE_MSB && (pixelValue == 1 || pixelValue == 2)) {
+    renderer.drawPixel(x, y, false);
+  } else if (renderMode == GfxRenderer::GRAYSCALE_LSB && pixelValue == 1) {
+    renderer.drawPixel(x, y, false);
+  }
+}

lib/Epub/Epub/converters/ImageDecoderFactory.cpp

@@ -0,0 +1,42 @@
+#include "ImageDecoderFactory.h"
+
+#include <HardwareSerial.h>
+
+#include <memory>
+#include <string>
+
+#include "JpegToFramebufferConverter.h"
+#include "PngToFramebufferConverter.h"
+
+std::unique_ptr<JpegToFramebufferConverter> ImageDecoderFactory::jpegDecoder = nullptr;
+std::unique_ptr<PngToFramebufferConverter> ImageDecoderFactory::pngDecoder = nullptr;
+
+ImageToFramebufferDecoder* ImageDecoderFactory::getDecoder(const std::string& imagePath) {
+  std::string ext = imagePath;
+  size_t dotPos = ext.rfind('.');
+  if (dotPos != std::string::npos) {
+    ext = ext.substr(dotPos);
+    for (auto& c : ext) {
+      c = tolower(c);
+    }
+  } else {
+    ext = "";
+  }
+
+  if (JpegToFramebufferConverter::supportsFormat(ext)) {
+    if (!jpegDecoder) {
+      jpegDecoder.reset(new JpegToFramebufferConverter());
+    }
+    return jpegDecoder.get();
+  } else if (PngToFramebufferConverter::supportsFormat(ext)) {
+    if (!pngDecoder) {
+      pngDecoder.reset(new PngToFramebufferConverter());
+    }
+    return pngDecoder.get();
+  }
+
+  Serial.printf("[%lu] [DEC] No decoder found for image: %s\n", millis(), imagePath.c_str());
+  return nullptr;
+}
+
+bool ImageDecoderFactory::isFormatSupported(const std::string& imagePath) { return getDecoder(imagePath) != nullptr; }

lib/Epub/Epub/converters/ImageDecoderFactory.h

@@ -0,0 +1,20 @@
+#pragma once
+#include <cstdint>
+#include <memory>
+#include <string>
+
+#include "ImageToFramebufferDecoder.h"
+
+class JpegToFramebufferConverter;
+class PngToFramebufferConverter;
+
+class ImageDecoderFactory {
+ public:
+  // Returns non-owning pointer - factory owns the decoder lifetime
+  static ImageToFramebufferDecoder* getDecoder(const std::string& imagePath);
+  static bool isFormatSupported(const std::string& imagePath);
+
+ private:
+  static std::unique_ptr<JpegToFramebufferConverter> jpegDecoder;
+  static std::unique_ptr<PngToFramebufferConverter> pngDecoder;
+};

lib/Epub/Epub/converters/ImageToFramebufferDecoder.cpp

@@ -0,0 +1,18 @@
+#include "ImageToFramebufferDecoder.h"
+
+#include <Arduino.h>
+#include <HardwareSerial.h>
+
+bool ImageToFramebufferDecoder::validateImageDimensions(int width, int height, const std::string& format) {
+  if (width * height > MAX_SOURCE_PIXELS) {
+    Serial.printf("[%lu] [IMG] Image too large (%dx%d = %d pixels %s), max supported: %d pixels\n", millis(), width,
+                  height, width * height, format.c_str(), MAX_SOURCE_PIXELS);
+    return false;
+  }
+  return true;
+}
+
+void ImageToFramebufferDecoder::warnUnsupportedFeature(const std::string& feature, const std::string& imagePath) {
+  Serial.printf("[%lu] [IMG] Warning: Unsupported feature '%s' in image '%s'. Image may not display correctly.\n",
+                millis(), feature.c_str(), imagePath.c_str());
+}

lib/Epub/Epub/converters/ImageToFramebufferDecoder.h

@@ -0,0 +1,40 @@
+#pragma once
+#include <SdFat.h>
+
+#include <memory>
+#include <string>
+
+class GfxRenderer;
+
+struct ImageDimensions {
+  int16_t width;
+  int16_t height;
+};
+
+struct RenderConfig {
+  int x, y;
+  int maxWidth, maxHeight;
+  bool useGrayscale = true;
+  bool useDithering = true;
+  bool performanceMode = false;
+  bool useExactDimensions = false;  // If true, use maxWidth/maxHeight as exact output size (no recalculation)
+  std::string cachePath;            // If non-empty, decoder will write pixel cache to this path
+};
+
+class ImageToFramebufferDecoder {
+ public:
+  virtual ~ImageToFramebufferDecoder() = default;
+
+  virtual bool decodeToFramebuffer(const std::string& imagePath, GfxRenderer& renderer, const RenderConfig& config) = 0;
+
+  virtual bool getDimensions(const std::string& imagePath, ImageDimensions& dims) const = 0;
+
+  virtual const char* getFormatName() const = 0;
+
+ protected:
+  // Size validation helpers
+  static constexpr int MAX_SOURCE_PIXELS = 3145728;  // 2048 * 1536
+
+  bool validateImageDimensions(int width, int height, const std::string& format);
+  void warnUnsupportedFeature(const std::string& feature, const std::string& imagePath);
+};

lib/Epub/Epub/converters/JpegToFramebufferConverter.cpp

@@ -0,0 +1,298 @@
+#include "JpegToFramebufferConverter.h"
+
+#include <GfxRenderer.h>
+#include <HardwareSerial.h>
+#include <SDCardManager.h>
+#include <SdFat.h>
+#include <picojpeg.h>
+
+#include <cstdio>
+#include <cstring>
+
+#include "DitherUtils.h"
+#include "PixelCache.h"
+
+struct JpegContext {
+  FsFile& file;
+  uint8_t buffer[512];
+  size_t bufferPos;
+  size_t bufferFilled;
+  JpegContext(FsFile& f) : file(f), bufferPos(0), bufferFilled(0) {}
+};
+
+bool JpegToFramebufferConverter::getDimensionsStatic(const std::string& imagePath, ImageDimensions& out) {
+  FsFile file;
+  if (!Storage.openFileForRead("JPG", imagePath, file)) {
+    Serial.printf("[%lu] [JPG] Failed to open file for dimensions: %s\n", millis(), imagePath.c_str());
+    return false;
+  }
+
+  JpegContext context(file);
+  pjpeg_image_info_t imageInfo;
+
+  int status = pjpeg_decode_init(&imageInfo, jpegReadCallback, &context, 0);
+  file.close();
+
+  if (status != 0) {
+    Serial.printf("[%lu] [JPG] Failed to init JPEG for dimensions: %d\n", millis(), status);
+    return false;
+  }
+
+  out.width = imageInfo.m_width;
+  out.height = imageInfo.m_height;
+  Serial.printf("[%lu] [JPG] Image dimensions: %dx%d\n", millis(), out.width, out.height);
+  return true;
+}
+
+bool JpegToFramebufferConverter::decodeToFramebuffer(const std::string& imagePath, GfxRenderer& renderer,
+                                                     const RenderConfig& config) {
+  Serial.printf("[%lu] [JPG] Decoding JPEG: %s\n", millis(), imagePath.c_str());
+
+  FsFile file;
+  if (!Storage.openFileForRead("JPG", imagePath, file)) {
+    Serial.printf("[%lu] [JPG] Failed to open file: %s\n", millis(), imagePath.c_str());
+    return false;
+  }
+
+  JpegContext context(file);
+  pjpeg_image_info_t imageInfo;
+
+  int status = pjpeg_decode_init(&imageInfo, jpegReadCallback, &context, 0);
+  if (status != 0) {
+    Serial.printf("[%lu] [JPG] picojpeg init failed: %d\n", millis(), status);
+    file.close();
+    return false;
+  }
+
+  if (!validateImageDimensions(imageInfo.m_width, imageInfo.m_height, "JPEG")) {
+    file.close();
+    return false;
+  }
+
+  // Calculate output dimensions
+  int destWidth, destHeight;
+  float scale;
+
+  if (config.useExactDimensions && config.maxWidth > 0 && config.maxHeight > 0) {
+    // Use exact dimensions as specified (avoids rounding mismatches with pre-calculated sizes)
+    destWidth = config.maxWidth;
+    destHeight = config.maxHeight;
+    scale = (float)destWidth / imageInfo.m_width;
+  } else {
+    // Calculate scale factor to fit within maxWidth/maxHeight
+    float scaleX = (config.maxWidth > 0 && imageInfo.m_width > config.maxWidth)
+                       ? (float)config.maxWidth / imageInfo.m_width
+                       : 1.0f;
+    float scaleY = (config.maxHeight > 0 && imageInfo.m_height > config.maxHeight)
+                       ? (float)config.maxHeight / imageInfo.m_height
+                       : 1.0f;
+    scale = (scaleX < scaleY) ? scaleX : scaleY;
+    if (scale > 1.0f) scale = 1.0f;
+
+    destWidth = (int)(imageInfo.m_width * scale);
+    destHeight = (int)(imageInfo.m_height * scale);
+  }
+
+  Serial.printf("[%lu] [JPG] JPEG %dx%d -> %dx%d (scale %.2f), scan type: %d, MCU: %dx%d\n", millis(),
+                imageInfo.m_width, imageInfo.m_height, destWidth, destHeight, scale, imageInfo.m_scanType,
+                imageInfo.m_MCUWidth, imageInfo.m_MCUHeight);
+
+  if (!imageInfo.m_pMCUBufR || !imageInfo.m_pMCUBufG || !imageInfo.m_pMCUBufB) {
+    Serial.printf("[%lu] [JPG] Null buffer pointers in imageInfo\n", millis());
+    file.close();
+    return false;
+  }
+
+  const int screenWidth = renderer.getScreenWidth();
+  const int screenHeight = renderer.getScreenHeight();
+
+  // Allocate pixel cache if cachePath is provided
+  PixelCache cache;
+  bool caching = !config.cachePath.empty();
+  if (caching) {
+    if (!cache.allocate(destWidth, destHeight, config.x, config.y)) {
+      Serial.printf("[%lu] [JPG] Failed to allocate cache buffer, continuing without caching\n", millis());
+      caching = false;
+    }
+  }
+
+  int mcuX = 0;
+  int mcuY = 0;
+
+  while (mcuY < imageInfo.m_MCUSPerCol) {
+    status = pjpeg_decode_mcu();
+    if (status == PJPG_NO_MORE_BLOCKS) {
+      break;
+    }
+    if (status != 0) {
+      Serial.printf("[%lu] [JPG] MCU decode failed: %d\n", millis(), status);
+      file.close();
+      return false;
+    }
+
+    // Source position in image coordinates
+    int srcStartX = mcuX * imageInfo.m_MCUWidth;
+    int srcStartY = mcuY * imageInfo.m_MCUHeight;
+
+    switch (imageInfo.m_scanType) {
+      case PJPG_GRAYSCALE:
+        for (int row = 0; row < 8; row++) {
+          int srcY = srcStartY + row;
+          int destY = config.y + (int)(srcY * scale);
+          if (destY >= screenHeight || destY >= config.y + destHeight) continue;
+          for (int col = 0; col < 8; col++) {
+            int srcX = srcStartX + col;
+            int destX = config.x + (int)(srcX * scale);
+            if (destX >= screenWidth || destX >= config.x + destWidth) continue;
+            uint8_t gray = imageInfo.m_pMCUBufR[row * 8 + col];
+            uint8_t dithered = config.useDithering ? applyBayerDither4Level(gray, destX, destY) : gray / 85;
+            if (dithered > 3) dithered = 3;
+            drawPixelWithRenderMode(renderer, destX, destY, dithered);
+            if (caching) cache.setPixel(destX, destY, dithered);
+          }
+        }
+        break;
+
+      case PJPG_YH1V1:
+        for (int row = 0; row < 8; row++) {
+          int srcY = srcStartY + row;
+          int destY = config.y + (int)(srcY * scale);
+          if (destY >= screenHeight || destY >= config.y + destHeight) continue;
+          for (int col = 0; col < 8; col++) {
+            int srcX = srcStartX + col;
+            int destX = config.x + (int)(srcX * scale);
+            if (destX >= screenWidth || destX >= config.x + destWidth) continue;
+            uint8_t r = imageInfo.m_pMCUBufR[row * 8 + col];
+            uint8_t g = imageInfo.m_pMCUBufG[row * 8 + col];
+            uint8_t b = imageInfo.m_pMCUBufB[row * 8 + col];
+            uint8_t gray = (uint8_t)((r * 77 + g * 150 + b * 29) >> 8);
+            uint8_t dithered = config.useDithering ? applyBayerDither4Level(gray, destX, destY) : gray / 85;
+            if (dithered > 3) dithered = 3;
+            drawPixelWithRenderMode(renderer, destX, destY, dithered);
+            if (caching) cache.setPixel(destX, destY, dithered);
+          }
+        }
+        break;
+
+      case PJPG_YH2V1:
+        for (int row = 0; row < 8; row++) {
+          int srcY = srcStartY + row;
+          int destY = config.y + (int)(srcY * scale);
+          if (destY >= screenHeight || destY >= config.y + destHeight) continue;
+          for (int col = 0; col < 16; col++) {
+            int srcX = srcStartX + col;
+            int destX = config.x + (int)(srcX * scale);
+            if (destX >= screenWidth || destX >= config.x + destWidth) continue;
+            int blockIndex = (col < 8) ? 0 : 1;
+            int pixelIndex = row * 8 + (col % 8);
+            uint8_t r = imageInfo.m_pMCUBufR[blockIndex * 64 + pixelIndex];
+            uint8_t g = imageInfo.m_pMCUBufG[blockIndex * 64 + pixelIndex];
+            uint8_t b = imageInfo.m_pMCUBufB[blockIndex * 64 + pixelIndex];
+            uint8_t gray = (uint8_t)((r * 77 + g * 150 + b * 29) >> 8);
+            uint8_t dithered = config.useDithering ? applyBayerDither4Level(gray, destX, destY) : gray / 85;
+            if (dithered > 3) dithered = 3;
+            drawPixelWithRenderMode(renderer, destX, destY, dithered);
+            if (caching) cache.setPixel(destX, destY, dithered);
+          }
+        }
+        break;
+
+      case PJPG_YH1V2:
+        for (int row = 0; row < 16; row++) {
+          int srcY = srcStartY + row;
+          int destY = config.y + (int)(srcY * scale);
+          if (destY >= screenHeight || destY >= config.y + destHeight) continue;
+          for (int col = 0; col < 8; col++) {
+            int srcX = srcStartX + col;
+            int destX = config.x + (int)(srcX * scale);
+            if (destX >= screenWidth || destX >= config.x + destWidth) continue;
+            int blockIndex = (row < 8) ? 0 : 1;
+            int pixelIndex = (row % 8) * 8 + col;
+            uint8_t r = imageInfo.m_pMCUBufR[blockIndex * 128 + pixelIndex];
+            uint8_t g = imageInfo.m_pMCUBufG[blockIndex * 128 + pixelIndex];
+            uint8_t b = imageInfo.m_pMCUBufB[blockIndex * 128 + pixelIndex];
+            uint8_t gray = (uint8_t)((r * 77 + g * 150 + b * 29) >> 8);
+            uint8_t dithered = config.useDithering ? applyBayerDither4Level(gray, destX, destY) : gray / 85;
+            if (dithered > 3) dithered = 3;
+            drawPixelWithRenderMode(renderer, destX, destY, dithered);
+            if (caching) cache.setPixel(destX, destY, dithered);
+          }
+        }
+        break;
+
+      case PJPG_YH2V2:
+        for (int row = 0; row < 16; row++) {
+          int srcY = srcStartY + row;
+          int destY = config.y + (int)(srcY * scale);
+          if (destY >= screenHeight || destY >= config.y + destHeight) continue;
+          for (int col = 0; col < 16; col++) {
+            int srcX = srcStartX + col;
+            int destX = config.x + (int)(srcX * scale);
+            if (destX >= screenWidth || destX >= config.x + destWidth) continue;
+            int blockX = (col < 8) ? 0 : 1;
+            int blockY = (row < 8) ? 0 : 1;
+            int blockIndex = blockY * 2 + blockX;
+            int pixelIndex = (row % 8) * 8 + (col % 8);
+            int blockOffset = blockIndex * 64;
+            uint8_t r = imageInfo.m_pMCUBufR[blockOffset + pixelIndex];
+            uint8_t g = imageInfo.m_pMCUBufG[blockOffset + pixelIndex];
+            uint8_t b = imageInfo.m_pMCUBufB[blockOffset + pixelIndex];
+            uint8_t gray = (uint8_t)((r * 77 + g * 150 + b * 29) >> 8);
+            uint8_t dithered = config.useDithering ? applyBayerDither4Level(gray, destX, destY) : gray / 85;
+            if (dithered > 3) dithered = 3;
+            drawPixelWithRenderMode(renderer, destX, destY, dithered);
+            if (caching) cache.setPixel(destX, destY, dithered);
+          }
+        }
+        break;
+    }
+
+    mcuX++;
+    if (mcuX >= imageInfo.m_MCUSPerRow) {
+      mcuX = 0;
+      mcuY++;
+    }
+  }
+
+  Serial.printf("[%lu] [JPG] Decoding complete\n", millis());
+  file.close();
+
+  // Write cache file if caching was enabled
+  if (caching) {
+    cache.writeToFile(config.cachePath);
+  }
+
+  return true;
+}
+
+unsigned char JpegToFramebufferConverter::jpegReadCallback(unsigned char* pBuf, unsigned char buf_size,
+                                                           unsigned char* pBytes_actually_read, void* pCallback_data) {
+  JpegContext* context = reinterpret_cast<JpegContext*>(pCallback_data);
+
+  if (context->bufferPos >= context->bufferFilled) {
+    int readCount = context->file.read(context->buffer, sizeof(context->buffer));
+    if (readCount <= 0) {
+      *pBytes_actually_read = 0;
+      return 0;
+    }
+    context->bufferFilled = readCount;
+    context->bufferPos = 0;
+  }
+
+  unsigned int bytesAvailable = context->bufferFilled - context->bufferPos;
+  unsigned int bytesToCopy = (bytesAvailable < buf_size) ? bytesAvailable : buf_size;
+
+  memcpy(pBuf, &context->buffer[context->bufferPos], bytesToCopy);
+  context->bufferPos += bytesToCopy;
+  *pBytes_actually_read = bytesToCopy;
+
+  return 0;
+}
+
+bool JpegToFramebufferConverter::supportsFormat(const std::string& extension) {
+  std::string ext = extension;
+  for (auto& c : ext) {
+    c = tolower(c);
+  }
+  return (ext == ".jpg" || ext == ".jpeg");
+}

lib/Epub/Epub/converters/JpegToFramebufferConverter.h

@@ -0,0 +1,24 @@
+#pragma once
+#include <stdint.h>
+
+#include <string>
+
+#include "ImageToFramebufferDecoder.h"
+
+class JpegToFramebufferConverter final : public ImageToFramebufferDecoder {
+ public:
+  static bool getDimensionsStatic(const std::string& imagePath, ImageDimensions& out);
+
+  bool decodeToFramebuffer(const std::string& imagePath, GfxRenderer& renderer, const RenderConfig& config) override;
+
+  bool getDimensions(const std::string& imagePath, ImageDimensions& dims) const override {
+    return getDimensionsStatic(imagePath, dims);
+  }
+
+  static bool supportsFormat(const std::string& extension);
+  const char* getFormatName() const override { return "JPEG"; }
+
+ private:
+  static unsigned char jpegReadCallback(unsigned char* pBuf, unsigned char buf_size,
+                                        unsigned char* pBytes_actually_read, void* pCallback_data);
+};

lib/Epub/Epub/converters/PixelCache.h

@@ -0,0 +1,85 @@
+#pragma once
+
+#include <HardwareSerial.h>
+#include <SDCardManager.h>
+#include <SdFat.h>
+#include <stdint.h>
+
+#include <cstring>
+#include <string>
+
+// Cache buffer for storing 2-bit pixels (4 levels) during decode.
+// Packs 4 pixels per byte, MSB first.
+struct PixelCache {
+  uint8_t* buffer;
+  int width;
+  int height;
+  int bytesPerRow;
+  int originX;  // config.x - to convert screen coords to cache coords
+  int originY;  // config.y
+
+  PixelCache() : buffer(nullptr), width(0), height(0), bytesPerRow(0), originX(0), originY(0) {}
+  PixelCache(const PixelCache&) = delete;
+  PixelCache& operator=(const PixelCache&) = delete;
+
+  static constexpr size_t MAX_CACHE_BYTES = 256 * 1024;  // 256KB limit for embedded targets
+
+  bool allocate(int w, int h, int ox, int oy) {
+    width = w;
+    height = h;
+    originX = ox;
+    originY = oy;
+    bytesPerRow = (w + 3) / 4;  // 2 bits per pixel, 4 pixels per byte
+    size_t bufferSize = (size_t)bytesPerRow * h;
+    if (bufferSize > MAX_CACHE_BYTES) {
+      Serial.printf("[%lu] [IMG] Cache buffer too large: %d bytes for %dx%d (limit %d)\n", millis(), bufferSize, w, h,
+                    MAX_CACHE_BYTES);
+      return false;
+    }
+    buffer = (uint8_t*)malloc(bufferSize);
+    if (buffer) {
+      memset(buffer, 0, bufferSize);
+      Serial.printf("[%lu] [IMG] Allocated cache buffer: %d bytes for %dx%d\n", millis(), bufferSize, w, h);
+    }
+    return buffer != nullptr;
+  }
+
+  void setPixel(int screenX, int screenY, uint8_t value) {
+    if (!buffer) return;
+    int localX = screenX - originX;
+    int localY = screenY - originY;
+    if (localX < 0 || localX >= width || localY < 0 || localY >= height) return;
+
+    int byteIdx = localY * bytesPerRow + localX / 4;
+    int bitShift = 6 - (localX % 4) * 2;  // MSB first: pixel 0 at bits 6-7
+    buffer[byteIdx] = (buffer[byteIdx] & ~(0x03 << bitShift)) | ((value & 0x03) << bitShift);
+  }
+
+  bool writeToFile(const std::string& cachePath) {
+    if (!buffer) return false;
+
+    FsFile cacheFile;
+    if (!Storage.openFileForWrite("IMG", cachePath, cacheFile)) {
+      Serial.printf("[%lu] [IMG] Failed to open cache file for writing: %s\n", millis(), cachePath.c_str());
+      return false;
+    }
+
+    uint16_t w = width;
+    uint16_t h = height;
+    cacheFile.write(&w, 2);
+    cacheFile.write(&h, 2);
+    cacheFile.write(buffer, bytesPerRow * height);
+    cacheFile.close();
+
+    Serial.printf("[%lu] [IMG] Cache written: %s (%dx%d, %d bytes)\n", millis(), cachePath.c_str(), width, height,
+                  4 + bytesPerRow * height);
+    return true;
+  }
+
+  ~PixelCache() {
+    if (buffer) {
+      free(buffer);
+      buffer = nullptr;
+    }
+  }
+};

lib/Epub/Epub/converters/PngToFramebufferConverter.cpp

@@ -0,0 +1,364 @@
+#include "PngToFramebufferConverter.h"
+
+#include <GfxRenderer.h>
+#include <HardwareSerial.h>
+#include <PNGdec.h>
+#include <SDCardManager.h>
+#include <SdFat.h>
+
+#include <cstdlib>
+#include <new>
+
+#include "DitherUtils.h"
+#include "PixelCache.h"
+
+namespace {
+
+// Context struct passed through PNGdec callbacks to avoid global mutable state.
+// The draw callback receives this via pDraw->pUser (set by png.decode()).
+// The file I/O callbacks receive the FsFile* via pFile->fHandle (set by pngOpen()).
+struct PngContext {
+  GfxRenderer* renderer;
+  const RenderConfig* config;
+  int screenWidth;
+  int screenHeight;
+
+  // Scaling state
+  float scale;
+  int srcWidth;
+  int srcHeight;
+  int dstWidth;
+  int dstHeight;
+  int lastDstY;  // Track last rendered destination Y to avoid duplicates
+
+  PixelCache cache;
+  bool caching;
+
+  uint8_t* grayLineBuffer;
+
+  PngContext()
+      : renderer(nullptr),
+        config(nullptr),
+        screenWidth(0),
+        screenHeight(0),
+        scale(1.0f),
+        srcWidth(0),
+        srcHeight(0),
+        dstWidth(0),
+        dstHeight(0),
+        lastDstY(-1),
+        caching(false),
+        grayLineBuffer(nullptr) {}
+};
+
+// File I/O callbacks use pFile->fHandle to access the FsFile*,
+// avoiding the need for global file state.
+void* pngOpenWithHandle(const char* filename, int32_t* size) {
+  FsFile* f = new FsFile();
+  if (!Storage.openFileForRead("PNG", std::string(filename), *f)) {
+    delete f;
+    return nullptr;
+  }
+  *size = f->size();
+  return f;
+}
+
+void pngCloseWithHandle(void* handle) {
+  FsFile* f = reinterpret_cast<FsFile*>(handle);
+  if (f) {
+    f->close();
+    delete f;
+  }
+}
+
+int32_t pngReadWithHandle(PNGFILE* pFile, uint8_t* pBuf, int32_t len) {
+  FsFile* f = reinterpret_cast<FsFile*>(pFile->fHandle);
+  if (!f) return 0;
+  return f->read(pBuf, len);
+}
+
+int32_t pngSeekWithHandle(PNGFILE* pFile, int32_t pos) {
+  FsFile* f = reinterpret_cast<FsFile*>(pFile->fHandle);
+  if (!f) return -1;
+  return f->seek(pos);
+}
+
+// The PNG decoder (PNGdec) is ~42 KB due to internal zlib decompression buffers.
+// We heap-allocate it on demand rather than using a static instance, so this memory
+// is only consumed while actually decoding/querying PNG images. This is critical on
+// the ESP32-C3 where total RAM is ~320 KB.
+constexpr size_t PNG_DECODER_APPROX_SIZE = 44 * 1024;                          // ~42 KB + overhead
+constexpr size_t MIN_FREE_HEAP_FOR_PNG = PNG_DECODER_APPROX_SIZE + 16 * 1024;  // decoder + 16 KB headroom
+
+// Convert entire source line to grayscale with alpha blending to white background.
+// For indexed PNGs with tRNS chunk, alpha values are stored at palette[768] onwards.
+// Processing the whole line at once improves cache locality and reduces per-pixel overhead.
+void convertLineToGray(uint8_t* pPixels, uint8_t* grayLine, int width, int pixelType, uint8_t* palette, int hasAlpha) {
+  switch (pixelType) {
+    case PNG_PIXEL_GRAYSCALE:
+      memcpy(grayLine, pPixels, width);
+      break;
+
+    case PNG_PIXEL_TRUECOLOR:
+      for (int x = 0; x < width; x++) {
+        uint8_t* p = &pPixels[x * 3];
+        grayLine[x] = (uint8_t)((p[0] * 77 + p[1] * 150 + p[2] * 29) >> 8);
+      }
+      break;
+
+    case PNG_PIXEL_INDEXED:
+      if (palette) {
+        if (hasAlpha) {
+          for (int x = 0; x < width; x++) {
+            uint8_t idx = pPixels[x];
+            uint8_t* p = &palette[idx * 3];
+            uint8_t gray = (uint8_t)((p[0] * 77 + p[1] * 150 + p[2] * 29) >> 8);
+            uint8_t alpha = palette[768 + idx];
+            grayLine[x] = (uint8_t)((gray * alpha + 255 * (255 - alpha)) / 255);
+          }
+        } else {
+          for (int x = 0; x < width; x++) {
+            uint8_t* p = &palette[pPixels[x] * 3];
+            grayLine[x] = (uint8_t)((p[0] * 77 + p[1] * 150 + p[2] * 29) >> 8);
+          }
+        }
+      } else {
+        memcpy(grayLine, pPixels, width);
+      }
+      break;
+
+    case PNG_PIXEL_GRAY_ALPHA:
+      for (int x = 0; x < width; x++) {
+        uint8_t gray = pPixels[x * 2];
+        uint8_t alpha = pPixels[x * 2 + 1];
+        grayLine[x] = (uint8_t)((gray * alpha + 255 * (255 - alpha)) / 255);
+      }
+      break;
+
+    case PNG_PIXEL_TRUECOLOR_ALPHA:
+      for (int x = 0; x < width; x++) {
+        uint8_t* p = &pPixels[x * 4];
+        uint8_t gray = (uint8_t)((p[0] * 77 + p[1] * 150 + p[2] * 29) >> 8);
+        uint8_t alpha = p[3];
+        grayLine[x] = (uint8_t)((gray * alpha + 255 * (255 - alpha)) / 255);
+      }
+      break;
+
+    default:
+      memset(grayLine, 128, width);
+      break;
+  }
+}
+
+int pngDrawCallback(PNGDRAW* pDraw) {
+  PngContext* ctx = reinterpret_cast<PngContext*>(pDraw->pUser);
+  if (!ctx || !ctx->config || !ctx->renderer || !ctx->grayLineBuffer) return 0;
+
+  int srcY = pDraw->y;
+  int srcWidth = ctx->srcWidth;
+
+  // Calculate destination Y with scaling
+  int dstY = (int)(srcY * ctx->scale);
+
+  // Skip if we already rendered this destination row (multiple source rows map to same dest)
+  if (dstY == ctx->lastDstY) return 1;
+  ctx->lastDstY = dstY;
+
+  // Check bounds
+  if (dstY >= ctx->dstHeight) return 1;
+
+  int outY = ctx->config->y + dstY;
+  if (outY >= ctx->screenHeight) return 1;
+
+  // Convert entire source line to grayscale (improves cache locality)
+  convertLineToGray(pDraw->pPixels, ctx->grayLineBuffer, srcWidth, pDraw->iPixelType, pDraw->pPalette,
+                    pDraw->iHasAlpha);
+
+  // Render scaled row using Bresenham-style integer stepping (no floating-point division)
+  int dstWidth = ctx->dstWidth;
+  int outXBase = ctx->config->x;
+  int screenWidth = ctx->screenWidth;
+  bool useDithering = ctx->config->useDithering;
+  bool caching = ctx->caching;
+
+  int srcX = 0;
+  int error = 0;
+
+  for (int dstX = 0; dstX < dstWidth; dstX++) {
+    int outX = outXBase + dstX;
+    if (outX < screenWidth) {
+      uint8_t gray = ctx->grayLineBuffer[srcX];
+
+      uint8_t ditheredGray;
+      if (useDithering) {
+        ditheredGray = applyBayerDither4Level(gray, outX, outY);
+      } else {
+        ditheredGray = gray / 85;
+        if (ditheredGray > 3) ditheredGray = 3;
+      }
+      drawPixelWithRenderMode(*ctx->renderer, outX, outY, ditheredGray);
+      if (caching) ctx->cache.setPixel(outX, outY, ditheredGray);
+    }
+
+    // Bresenham-style stepping: advance srcX based on ratio srcWidth/dstWidth
+    error += srcWidth;
+    while (error >= dstWidth) {
+      error -= dstWidth;
+      srcX++;
+    }
+  }
+
+  return 1;
+}
+
+}  // namespace
+
+bool PngToFramebufferConverter::getDimensionsStatic(const std::string& imagePath, ImageDimensions& out) {
+  size_t freeHeap = ESP.getFreeHeap();
+  if (freeHeap < MIN_FREE_HEAP_FOR_PNG) {
+    Serial.printf("[%lu] [PNG] Not enough heap for PNG decoder (%u free, need %u)\n", millis(), freeHeap,
+                  MIN_FREE_HEAP_FOR_PNG);
+    return false;
+  }
+
+  PNG* png = new (std::nothrow) PNG();
+  if (!png) {
+    Serial.printf("[%lu] [PNG] Failed to allocate PNG decoder for dimensions\n", millis());
+    return false;
+  }
+
+  int rc = png->open(imagePath.c_str(), pngOpenWithHandle, pngCloseWithHandle, pngReadWithHandle, pngSeekWithHandle,
+                     nullptr);
+
+  if (rc != 0) {
+    Serial.printf("[%lu] [PNG] Failed to open PNG for dimensions: %d\n", millis(), rc);
+    delete png;
+    return false;
+  }
+
+  out.width = png->getWidth();
+  out.height = png->getHeight();
+
+  png->close();
+  delete png;
+  return true;
+}
+
+bool PngToFramebufferConverter::decodeToFramebuffer(const std::string& imagePath, GfxRenderer& renderer,
+                                                    const RenderConfig& config) {
+  Serial.printf("[%lu] [PNG] Decoding PNG: %s\n", millis(), imagePath.c_str());
+
+  size_t freeHeap = ESP.getFreeHeap();
+  if (freeHeap < MIN_FREE_HEAP_FOR_PNG) {
+    Serial.printf("[%lu] [PNG] Not enough heap for PNG decoder (%u free, need %u)\n", millis(), freeHeap,
+                  MIN_FREE_HEAP_FOR_PNG);
+    return false;
+  }
+
+  // Heap-allocate PNG decoder (~42 KB) - freed at end of function
+  PNG* png = new (std::nothrow) PNG();
+  if (!png) {
+    Serial.printf("[%lu] [PNG] Failed to allocate PNG decoder\n", millis());
+    return false;
+  }
+
+  PngContext ctx;
+  ctx.renderer = &renderer;
+  ctx.config = &config;
+  ctx.screenWidth = renderer.getScreenWidth();
+  ctx.screenHeight = renderer.getScreenHeight();
+
+  int rc = png->open(imagePath.c_str(), pngOpenWithHandle, pngCloseWithHandle, pngReadWithHandle, pngSeekWithHandle,
+                     pngDrawCallback);
+  if (rc != PNG_SUCCESS) {
+    Serial.printf("[%lu] [PNG] Failed to open PNG: %d\n", millis(), rc);
+    delete png;
+    return false;
+  }
+
+  if (!validateImageDimensions(png->getWidth(), png->getHeight(), "PNG")) {
+    png->close();
+    delete png;
+    return false;
+  }
+
+  // Calculate output dimensions
+  ctx.srcWidth = png->getWidth();
+  ctx.srcHeight = png->getHeight();
+
+  if (config.useExactDimensions && config.maxWidth > 0 && config.maxHeight > 0) {
+    // Use exact dimensions as specified (avoids rounding mismatches with pre-calculated sizes)
+    ctx.dstWidth = config.maxWidth;
+    ctx.dstHeight = config.maxHeight;
+    ctx.scale = (float)ctx.dstWidth / ctx.srcWidth;
+  } else {
+    // Calculate scale factor to fit within maxWidth/maxHeight
+    float scaleX = (float)config.maxWidth / ctx.srcWidth;
+    float scaleY = (float)config.maxHeight / ctx.srcHeight;
+    ctx.scale = (scaleX < scaleY) ? scaleX : scaleY;
+    if (ctx.scale > 1.0f) ctx.scale = 1.0f;  // Don't upscale
+
+    ctx.dstWidth = (int)(ctx.srcWidth * ctx.scale);
+    ctx.dstHeight = (int)(ctx.srcHeight * ctx.scale);
+  }
+  ctx.lastDstY = -1;  // Reset row tracking
+
+  Serial.printf("[%lu] [PNG] PNG %dx%d -> %dx%d (scale %.2f), bpp: %d\n", millis(), ctx.srcWidth, ctx.srcHeight,
+                ctx.dstWidth, ctx.dstHeight, ctx.scale, png->getBpp());
+
+  if (png->getBpp() != 8) {
+    warnUnsupportedFeature("bit depth (" + std::to_string(png->getBpp()) + "bpp)", imagePath);
+  }
+
+  // Allocate grayscale line buffer on demand (~3.2 KB) - freed after decode
+  const size_t grayBufSize = PNG_MAX_BUFFERED_PIXELS / 2;
+  ctx.grayLineBuffer = static_cast<uint8_t*>(malloc(grayBufSize));
+  if (!ctx.grayLineBuffer) {
+    Serial.printf("[%lu] [PNG] Failed to allocate gray line buffer\n", millis());
+    png->close();
+    delete png;
+    return false;
+  }
+
+  // Allocate cache buffer using SCALED dimensions
+  ctx.caching = !config.cachePath.empty();
+  if (ctx.caching) {
+    if (!ctx.cache.allocate(ctx.dstWidth, ctx.dstHeight, config.x, config.y)) {
+      Serial.printf("[%lu] [PNG] Failed to allocate cache buffer, continuing without caching\n", millis());
+      ctx.caching = false;
+    }
+  }
+
+  unsigned long decodeStart = millis();
+  rc = png->decode(&ctx, 0);
+  unsigned long decodeTime = millis() - decodeStart;
+
+  free(ctx.grayLineBuffer);
+  ctx.grayLineBuffer = nullptr;
+
+  if (rc != PNG_SUCCESS) {
+    Serial.printf("[%lu] [PNG] Decode failed: %d\n", millis(), rc);
+    png->close();
+    delete png;
+    return false;
+  }
+
+  png->close();
+  delete png;
+  Serial.printf("[%lu] [PNG] PNG decoding complete - render time: %lu ms\n", millis(), decodeTime);
+
+  // Write cache file if caching was enabled and buffer was allocated
+  if (ctx.caching) {
+    ctx.cache.writeToFile(config.cachePath);
+  }
+
+  return true;
+}
+
+bool PngToFramebufferConverter::supportsFormat(const std::string& extension) {
+  std::string ext = extension;
+  for (auto& c : ext) {
+    c = tolower(c);
+  }
+  return (ext == ".png");
+}

lib/Epub/Epub/converters/PngToFramebufferConverter.h

@@ -0,0 +1,17 @@
+#pragma once
+
+#include "ImageToFramebufferDecoder.h"
+
+class PngToFramebufferConverter final : public ImageToFramebufferDecoder {
+ public:
+  static bool getDimensionsStatic(const std::string& imagePath, ImageDimensions& out);
+
+  bool decodeToFramebuffer(const std::string& imagePath, GfxRenderer& renderer, const RenderConfig& config) override;
+
+  bool getDimensions(const std::string& imagePath, ImageDimensions& dims) const override {
+    return getDimensionsStatic(imagePath, dims);
+  }
+
+  static bool supportsFormat(const std::string& extension);
+  const char* getFormatName() const override { return "PNG"; }
+};

lib/Epub/Epub/css/CssParser.cpp

@@ -1,144 +1,57 @@
 #include "CssParser.h"
 
+#include <Arduino.h>
 #include <Logging.h>
 
 #include <algorithm>
+#include <array>
 #include <cctype>
+#include <string_view>
 
 namespace {
 
+// Stack-allocated string buffer to avoid heap reallocations during parsing
+// Provides string-like interface with fixed capacity
+struct StackBuffer {
+  static constexpr size_t CAPACITY = 1024;
+  char data[CAPACITY];
+  size_t len = 0;
+
+  void push_back(char c) {
+    if (len < CAPACITY - 1) {
+      data[len++] = c;
+    }
+  }
+
+  void clear() { len = 0; }
+  bool empty() const { return len == 0; }
+  size_t size() const { return len; }
+
+  // Get string view of current content (zero-copy)
+  std::string_view view() const { return std::string_view(data, len); }
+
+  // Convert to string for passing to functions (single allocation)
+  std::string str() const { return std::string(data, len); }
+};
+
 // Buffer size for reading CSS files
 constexpr size_t READ_BUFFER_SIZE = 512;
 
-// Maximum CSS file size we'll process (prevent memory issues)
-constexpr size_t MAX_CSS_SIZE = 64 * 1024;
+// Maximum number of CSS rules to store in the selector map
+// Prevents unbounded memory growth from pathological CSS files
+constexpr size_t MAX_RULES = 1500;
+
+// Minimum free heap required to apply CSS during rendering
+// If below this threshold, we skip CSS to avoid display artifacts.
+constexpr size_t MIN_FREE_HEAP_FOR_CSS = 48 * 1024;
+
+// Maximum length for a single selector string
+// Prevents parsing of extremely long or malformed selectors
+constexpr size_t MAX_SELECTOR_LENGTH = 256;
 
 // Check if character is CSS whitespace
 bool isCssWhitespace(const char c) { return c == ' ' || c == '\t' || c == '\n' || c == '\r' || c == '\f'; }
 
-// Read entire file into string (with size limit)
-std::string readFileContent(FsFile& file) {
-  std::string content;
-  content.reserve(std::min(static_cast<size_t>(file.size()), MAX_CSS_SIZE));
-
-  char buffer[READ_BUFFER_SIZE];
-  while (file.available() && content.size() < MAX_CSS_SIZE) {
-    const int bytesRead = file.read(buffer, sizeof(buffer));
-    if (bytesRead <= 0) break;
-    content.append(buffer, bytesRead);
-  }
-  return content;
-}
-
-// Remove CSS comments (/* ... */) from content
-std::string stripComments(const std::string& css) {
-  std::string result;
-  result.reserve(css.size());
-
-  size_t pos = 0;
-  while (pos < css.size()) {
-    // Look for start of comment
-    if (pos + 1 < css.size() && css[pos] == '/' && css[pos + 1] == '*') {
-      // Find end of comment
-      const size_t endPos = css.find("*/", pos + 2);
-      if (endPos == std::string::npos) {
-        // Unterminated comment - skip rest of file
-        break;
-      }
-      pos = endPos + 2;
-    } else {
-      result.push_back(css[pos]);
-      ++pos;
-    }
-  }
-  return result;
-}
-
-// Skip @-rules (like @media, @import, @font-face)
-// Returns position after the @-rule
-size_t skipAtRule(const std::string& css, const size_t start) {
-  // Find the end - either semicolon (simple @-rule) or matching brace
-  size_t pos = start + 1;  // Skip the '@'
-
-  // Skip identifier
-  while (pos < css.size() && (std::isalnum(css[pos]) || css[pos] == '-')) {
-    ++pos;
-  }
-
-  // Look for { or ;
-  int braceDepth = 0;
-  while (pos < css.size()) {
-    const char c = css[pos];
-    if (c == '{') {
-      ++braceDepth;
-    } else if (c == '}') {
-      --braceDepth;
-      if (braceDepth == 0) {
-        return pos + 1;
-      }
-    } else if (c == ';' && braceDepth == 0) {
-      return pos + 1;
-    }
-    ++pos;
-  }
-  return css.size();
-}
-
-// Extract next rule from CSS content
-// Returns true if a rule was found, with selector and body filled
-bool extractNextRule(const std::string& css, size_t& pos, std::string& selector, std::string& body) {
-  selector.clear();
-  body.clear();
-
-  // Skip whitespace and @-rules until we find a regular rule
-  while (pos < css.size()) {
-    // Skip whitespace
-    while (pos < css.size() && isCssWhitespace(css[pos])) {
-      ++pos;
-    }
-
-    if (pos >= css.size()) return false;
-
-    // Handle @-rules iteratively (avoids recursion/stack overflow)
-    if (css[pos] == '@') {
-      pos = skipAtRule(css, pos);
-      continue;  // Try again after skipping the @-rule
-    }
-
-    break;  // Found start of a regular rule
-  }
-
-  if (pos >= css.size()) return false;
-
-  // Find opening brace
-  const size_t bracePos = css.find('{', pos);
-  if (bracePos == std::string::npos) return false;
-
-  // Extract selector (everything before the brace)
-  selector = css.substr(pos, bracePos - pos);
-
-  // Find matching closing brace
-  int depth = 1;
-  const size_t bodyStart = bracePos + 1;
-  size_t bodyEnd = bodyStart;
-
-  while (bodyEnd < css.size() && depth > 0) {
-    if (css[bodyEnd] == '{')
-      ++depth;
-    else if (css[bodyEnd] == '}')
-      --depth;
-    ++bodyEnd;
-  }
-
-  // Extract body (between braces)
-  if (bodyEnd > bodyStart) {
-    body = css.substr(bodyStart, bodyEnd - bodyStart - 1);
-  }
-
-  pos = bodyEnd;
-  return true;
-}
-
 }  // anonymous namespace
 
 // String utilities implementation
@@ -167,6 +80,28 @@ std::string CssParser::normalized(const std::string& s) {
   return result;
 }
 
+void CssParser::normalizedInto(const std::string& s, std::string& out) {
+  out.clear();
+  out.reserve(s.size());
+
+  bool inSpace = true;  // Start true to skip leading space
+  for (const char c : s) {
+    if (isCssWhitespace(c)) {
+      if (!inSpace) {
+        out.push_back(' ');
+        inSpace = true;
+      }
+    } else {
+      out.push_back(static_cast<char>(std::tolower(static_cast<unsigned char>(c))));
+      inSpace = false;
+    }
+  }
+
+  if (!out.empty() && out.back() == ' ') {
+    out.pop_back();
+  }
+}
+
 std::vector<std::string> CssParser::splitOnChar(const std::string& s, const char delimiter) {
   std::vector<std::string> parts;
   size_t start = 0;
@@ -290,129 +225,98 @@ CssLength CssParser::interpretLength(const std::string& val) {
 
   return CssLength{numericValue, unit};
 }
-
-int8_t CssParser::interpretSpacing(const std::string& val) {
-  const std::string v = normalized(val);
-  if (v.empty()) return 0;
-
-  // For spacing, we convert to "lines" (discrete units for e-ink)
-  // 1em ≈ 1 line, percentages based on ~30 lines per page
-
-  float multiplier = 0.0f;
-  size_t unitStart = v.size();
-
-  for (size_t i = 0; i < v.size(); ++i) {
-    const char c = v[i];
-    if (!std::isdigit(c) && c != '.' && c != '-' && c != '+') {
-      unitStart = i;
-      break;
-    }
-  }
-
-  const std::string numPart = v.substr(0, unitStart);
-  const std::string unitPart = v.substr(unitStart);
-
-  if (unitPart == "em" || unitPart == "rem") {
-    multiplier = 1.0f;  // 1em = 1 line
-  } else if (unitPart == "%") {
-    multiplier = 0.3f;  // ~30 lines per page, so 10% = 3 lines
-  } else {
-    return 0;  // Unsupported unit for spacing
-  }
-
-  char* endPtr = nullptr;
-  const float numericValue = std::strtof(numPart.c_str(), &endPtr);
-
-  if (endPtr == numPart.c_str()) return 0;
-
-  int lines = static_cast<int>(numericValue * multiplier);
-
-  // Clamp to reasonable range (0-2 lines)
-  if (lines < 0) lines = 0;
-  if (lines > 2) lines = 2;
-
-  return static_cast<int8_t>(lines);
-}
-
 // Declaration parsing
 
+void CssParser::parseDeclarationIntoStyle(const std::string& decl, CssStyle& style, std::string& propNameBuf,
+                                          std::string& propValueBuf) {
+  const size_t colonPos = decl.find(':');
+  if (colonPos == std::string::npos || colonPos == 0) return;
+
+  normalizedInto(decl.substr(0, colonPos), propNameBuf);
+  normalizedInto(decl.substr(colonPos + 1), propValueBuf);
+
+  if (propNameBuf.empty() || propValueBuf.empty()) return;
+
+  if (propNameBuf == "text-align") {
+    style.textAlign = interpretAlignment(propValueBuf);
+    style.defined.textAlign = 1;
+  } else if (propNameBuf == "font-style") {
+    style.fontStyle = interpretFontStyle(propValueBuf);
+    style.defined.fontStyle = 1;
+  } else if (propNameBuf == "font-weight") {
+    style.fontWeight = interpretFontWeight(propValueBuf);
+    style.defined.fontWeight = 1;
+  } else if (propNameBuf == "text-decoration" || propNameBuf == "text-decoration-line") {
+    style.textDecoration = interpretDecoration(propValueBuf);
+    style.defined.textDecoration = 1;
+  } else if (propNameBuf == "text-indent") {
+    style.textIndent = interpretLength(propValueBuf);
+    style.defined.textIndent = 1;
+  } else if (propNameBuf == "margin-top") {
+    style.marginTop = interpretLength(propValueBuf);
+    style.defined.marginTop = 1;
+  } else if (propNameBuf == "margin-bottom") {
+    style.marginBottom = interpretLength(propValueBuf);
+    style.defined.marginBottom = 1;
+  } else if (propNameBuf == "margin-left") {
+    style.marginLeft = interpretLength(propValueBuf);
+    style.defined.marginLeft = 1;
+  } else if (propNameBuf == "margin-right") {
+    style.marginRight = interpretLength(propValueBuf);
+    style.defined.marginRight = 1;
+  } else if (propNameBuf == "margin") {
+    const auto values = splitWhitespace(propValueBuf);
+    if (!values.empty()) {
+      style.marginTop = interpretLength(values[0]);
+      style.marginRight = values.size() >= 2 ? interpretLength(values[1]) : style.marginTop;
+      style.marginBottom = values.size() >= 3 ? interpretLength(values[2]) : style.marginTop;
+      style.marginLeft = values.size() >= 4 ? interpretLength(values[3]) : style.marginRight;
+      style.defined.marginTop = style.defined.marginRight = style.defined.marginBottom = style.defined.marginLeft = 1;
+    }
+  } else if (propNameBuf == "padding-top") {
+    style.paddingTop = interpretLength(propValueBuf);
+    style.defined.paddingTop = 1;
+  } else if (propNameBuf == "padding-bottom") {
+    style.paddingBottom = interpretLength(propValueBuf);
+    style.defined.paddingBottom = 1;
+  } else if (propNameBuf == "padding-left") {
+    style.paddingLeft = interpretLength(propValueBuf);
+    style.defined.paddingLeft = 1;
+  } else if (propNameBuf == "padding-right") {
+    style.paddingRight = interpretLength(propValueBuf);
+    style.defined.paddingRight = 1;
+  } else if (propNameBuf == "padding") {
+    const auto values = splitWhitespace(propValueBuf);
+    if (!values.empty()) {
+      style.paddingTop = interpretLength(values[0]);
+      style.paddingRight = values.size() >= 2 ? interpretLength(values[1]) : style.paddingTop;
+      style.paddingBottom = values.size() >= 3 ? interpretLength(values[2]) : style.paddingTop;
+      style.paddingLeft = values.size() >= 4 ? interpretLength(values[3]) : style.paddingRight;
+      style.defined.paddingTop = style.defined.paddingRight = style.defined.paddingBottom = style.defined.paddingLeft =
+          1;
+    }
+  } else if (propNameBuf == "width") {
+    style.width = interpretLength(propValueBuf);
+    style.defined.width = 1;
+  }
+}
+
 CssStyle CssParser::parseDeclarations(const std::string& declBlock) {
   CssStyle style;
+  std::string propNameBuf;
+  std::string propValueBuf;
 
-  // Split declarations by semicolon
-  const auto declarations = splitOnChar(declBlock, ';');
-
-  for (const auto& decl : declarations) {
-    // Find colon separator
-    const size_t colonPos = decl.find(':');
-    if (colonPos == std::string::npos || colonPos == 0) continue;
-
-    std::string propName = normalized(decl.substr(0, colonPos));
-    std::string propValue = normalized(decl.substr(colonPos + 1));
-
-    if (propName.empty() || propValue.empty()) continue;
-
-    // Match property and set value
-    if (propName == "text-align") {
-      style.textAlign = interpretAlignment(propValue);
-      style.defined.textAlign = 1;
-    } else if (propName == "font-style") {
-      style.fontStyle = interpretFontStyle(propValue);
-      style.defined.fontStyle = 1;
-    } else if (propName == "font-weight") {
-      style.fontWeight = interpretFontWeight(propValue);
-      style.defined.fontWeight = 1;
-    } else if (propName == "text-decoration" || propName == "text-decoration-line") {
-      style.textDecoration = interpretDecoration(propValue);
-      style.defined.textDecoration = 1;
-    } else if (propName == "text-indent") {
-      style.textIndent = interpretLength(propValue);
-      style.defined.textIndent = 1;
-    } else if (propName == "margin-top") {
-      style.marginTop = interpretLength(propValue);
-      style.defined.marginTop = 1;
-    } else if (propName == "margin-bottom") {
-      style.marginBottom = interpretLength(propValue);
-      style.defined.marginBottom = 1;
-    } else if (propName == "margin-left") {
-      style.marginLeft = interpretLength(propValue);
-      style.defined.marginLeft = 1;
-    } else if (propName == "margin-right") {
-      style.marginRight = interpretLength(propValue);
-      style.defined.marginRight = 1;
-    } else if (propName == "margin") {
-      // Shorthand: 1-4 values for top, right, bottom, left
-      const auto values = splitWhitespace(propValue);
-      if (!values.empty()) {
-        style.marginTop = interpretLength(values[0]);
-        style.marginRight = values.size() >= 2 ? interpretLength(values[1]) : style.marginTop;
-        style.marginBottom = values.size() >= 3 ? interpretLength(values[2]) : style.marginTop;
-        style.marginLeft = values.size() >= 4 ? interpretLength(values[3]) : style.marginRight;
-        style.defined.marginTop = style.defined.marginRight = style.defined.marginBottom = style.defined.marginLeft = 1;
-      }
-    } else if (propName == "padding-top") {
-      style.paddingTop = interpretLength(propValue);
-      style.defined.paddingTop = 1;
-    } else if (propName == "padding-bottom") {
-      style.paddingBottom = interpretLength(propValue);
-      style.defined.paddingBottom = 1;
-    } else if (propName == "padding-left") {
-      style.paddingLeft = interpretLength(propValue);
-      style.defined.paddingLeft = 1;
-    } else if (propName == "padding-right") {
-      style.paddingRight = interpretLength(propValue);
-      style.defined.paddingRight = 1;
-    } else if (propName == "padding") {
-      // Shorthand: 1-4 values for top, right, bottom, left
-      const auto values = splitWhitespace(propValue);
-      if (!values.empty()) {
-        style.paddingTop = interpretLength(values[0]);
-        style.paddingRight = values.size() >= 2 ? interpretLength(values[1]) : style.paddingTop;
-        style.paddingBottom = values.size() >= 3 ? interpretLength(values[2]) : style.paddingTop;
-        style.paddingLeft = values.size() >= 4 ? interpretLength(values[3]) : style.paddingRight;
-        style.defined.paddingTop = style.defined.paddingRight = style.defined.paddingBottom =
-            style.defined.paddingLeft = 1;
+  size_t start = 0;
+  for (size_t i = 0; i <= declBlock.size(); ++i) {
+    if (i == declBlock.size() || declBlock[i] == ';') {
+      if (i > start) {
+        const size_t len = i - start;
+        std::string decl = declBlock.substr(start, len);
+        if (!decl.empty()) {
+          parseDeclarationIntoStyle(decl, style, propNameBuf, propValueBuf);
+        }
       }
+      start = i + 1;
     }
   }
 
@@ -421,20 +325,33 @@ CssStyle CssParser::parseDeclarations(const std::string& declBlock) {
 
 // Rule processing
 
-void CssParser::processRuleBlock(const std::string& selectorGroup, const std::string& declarations) {
-  const CssStyle style = parseDeclarations(declarations);
-
-  // Only store if any properties were set
-  if (!style.defined.anySet()) return;
+void CssParser::processRuleBlockWithStyle(const std::string& selectorGroup, const CssStyle& style) {
+  // Check if we've reached the rule limit before processing
+  if (rulesBySelector_.size() >= MAX_RULES) {
+    LOG_DBG("CSS", "Reached max rules limit (%zu), stopping CSS parsing", MAX_RULES);
+    return;
+  }
 
   // Handle comma-separated selectors
   const auto selectors = splitOnChar(selectorGroup, ',');
 
   for (const auto& sel : selectors) {
+    // Validate selector length before processing
+    if (sel.size() > MAX_SELECTOR_LENGTH) {
+      LOG_DBG("CSS", "Selector too long (%zu > %zu), skipping", sel.size(), MAX_SELECTOR_LENGTH);
+      continue;
+    }
+
     // Normalize the selector
     std::string key = normalized(sel);
     if (key.empty()) continue;
 
+    // Skip if this would exceed the rule limit
+    if (rulesBySelector_.size() >= MAX_RULES) {
+      LOG_DBG("CSS", "Reached max rules limit, stopping selector processing");
+      return;
+    }
+
     // Store or merge with existing
     auto it = rulesBySelector_.find(key);
     if (it != rulesBySelector_.end()) {
@@ -453,30 +370,158 @@ bool CssParser::loadFromStream(FsFile& source) {
     return false;
   }
 
-  // Read file content
-  const std::string content = readFileContent(source);
-  if (content.empty()) {
-    return true;  // Empty file is valid
+  size_t totalRead = 0;
+
+  // Use stack-allocated buffers for parsing to avoid heap reallocations
+  StackBuffer selector;
+  StackBuffer declBuffer;
+  // Keep these as std::string since they're passed by reference to parseDeclarationIntoStyle
+  std::string propNameBuf;
+  std::string propValueBuf;
+
+  bool inComment = false;
+  bool maybeSlash = false;
+  bool prevStar = false;
+
+  bool inAtRule = false;
+  int atDepth = 0;
+
+  int bodyDepth = 0;
+  bool skippingRule = false;
+  CssStyle currentStyle;
+
+  auto handleChar = [&](const char c) {
+    if (inAtRule) {
+      if (c == '{') {
+        ++atDepth;
+      } else if (c == '}') {
+        if (atDepth > 0) --atDepth;
+        if (atDepth == 0) inAtRule = false;
+      } else if (c == ';' && atDepth == 0) {
+        inAtRule = false;
+      }
+      return;
+    }
+
+    if (bodyDepth == 0) {
+      if (selector.empty() && isCssWhitespace(c)) {
+        return;
+      }
+      if (c == '@' && selector.empty()) {
+        inAtRule = true;
+        atDepth = 0;
+        return;
+      }
+      if (c == '{') {
+        bodyDepth = 1;
+        currentStyle = CssStyle{};
+        declBuffer.clear();
+        if (selector.size() > MAX_SELECTOR_LENGTH * 4) {
+          skippingRule = true;
+        }
+        return;
+      }
+      selector.push_back(c);
+      return;
+    }
+
+    // bodyDepth > 0
+    if (c == '{') {
+      ++bodyDepth;
+      return;
+    }
+    if (c == '}') {
+      --bodyDepth;
+      if (bodyDepth == 0) {
+        if (!skippingRule && !declBuffer.empty()) {
+          parseDeclarationIntoStyle(declBuffer.str(), currentStyle, propNameBuf, propValueBuf);
+        }
+        if (!skippingRule) {
+          processRuleBlockWithStyle(selector.str(), currentStyle);
+        }
+        selector.clear();
+        declBuffer.clear();
+        skippingRule = false;
+        return;
+      }
+      return;
+    }
+    if (bodyDepth > 1) {
+      return;
+    }
+    if (!skippingRule) {
+      if (c == ';') {
+        if (!declBuffer.empty()) {
+          parseDeclarationIntoStyle(declBuffer.str(), currentStyle, propNameBuf, propValueBuf);
+          declBuffer.clear();
+        }
+      } else {
+        declBuffer.push_back(c);
+      }
+    }
+  };
+
+  char buffer[READ_BUFFER_SIZE];
+  while (source.available()) {
+    int bytesRead = source.read(buffer, sizeof(buffer));
+    if (bytesRead <= 0) break;
+
+    totalRead += static_cast<size_t>(bytesRead);
+
+    for (int i = 0; i < bytesRead; ++i) {
+      const char c = buffer[i];
+
+      if (inComment) {
+        if (prevStar && c == '/') {
+          inComment = false;
+          prevStar = false;
+          continue;
+        }
+        prevStar = c == '*';
+        continue;
+      }
+
+      if (maybeSlash) {
+        if (c == '*') {
+          inComment = true;
+          maybeSlash = false;
+          prevStar = false;
+          continue;
+        }
+        handleChar('/');
+        maybeSlash = false;
+        // fall through to process current char
+      }
+
+      if (c == '/') {
+        maybeSlash = true;
+        continue;
+      }
+
+      handleChar(c);
+    }
   }
 
-  // Remove comments
-  const std::string cleaned = stripComments(content);
-
-  // Parse rules
-  size_t pos = 0;
-  std::string selector, body;
-
-  while (extractNextRule(cleaned, pos, selector, body)) {
-    processRuleBlock(selector, body);
+  if (maybeSlash) {
+    handleChar('/');
   }
 
-  LOG_DBG("CSS", "Parsed %zu rules", rulesBySelector_.size());
+  LOG_DBG("CSS", "Parsed %zu rules from %zu bytes", rulesBySelector_.size(), totalRead);
   return true;
 }
 
 // Style resolution
 
 CssStyle CssParser::resolveStyle(const std::string& tagName, const std::string& classAttr) const {
+  static bool lowHeapWarningLogged = false;
+  if (ESP.getFreeHeap() < MIN_FREE_HEAP_FOR_CSS) {
+    if (!lowHeapWarningLogged) {
+      lowHeapWarningLogged = true;
+      LOG_DBG("CSS", "Warning: low heap (%u bytes) below MIN_FREE_HEAP_FOR_CSS (%u), returning empty style",
+              ESP.getFreeHeap(), static_cast<unsigned>(MIN_FREE_HEAP_FOR_CSS));
+    }
+    return CssStyle{};
+  }
   CssStyle result;
   const std::string tag = normalized(tagName);
 
@@ -521,9 +566,17 @@ CssStyle CssParser::parseInlineStyle(const std::string& styleValue) { return par
 
 // Cache format version - increment when format changes
 constexpr uint8_t CSS_CACHE_VERSION = 2;
+constexpr char rulesCache[] = "/css_rules.cache";
 
-bool CssParser::saveToCache(FsFile& file) const {
-  if (!file) {
+bool CssParser::hasCache() const { return Storage.exists((cachePath + rulesCache).c_str()); }
+
+bool CssParser::saveToCache() const {
+  if (cachePath.empty()) {
+    return false;
+  }
+
+  FsFile file;
+  if (!Storage.openFileForWrite("CSS", cachePath + rulesCache, file)) {
     return false;
   }
 
@@ -583,11 +636,17 @@ bool CssParser::saveToCache(FsFile& file) const {
   }
 
   LOG_DBG("CSS", "Saved %u rules to cache", ruleCount);
+  file.close();
   return true;
 }
 
-bool CssParser::loadFromCache(FsFile& file) {
-  if (!file) {
+bool CssParser::loadFromCache() {
+  if (cachePath.empty()) {
+    return false;
+  }
+
+  FsFile file;
+  if (!Storage.openFileForRead("CSS", cachePath + rulesCache, file)) {
     return false;
   }
 
@@ -598,12 +657,14 @@ bool CssParser::loadFromCache(FsFile& file) {
   uint8_t version = 0;
   if (file.read(&version, 1) != 1 || version != CSS_CACHE_VERSION) {
     LOG_DBG("CSS", "Cache version mismatch (got %u, expected %u)", version, CSS_CACHE_VERSION);
+    file.close();
     return false;
   }
 
   // Read rule count
   uint16_t ruleCount = 0;
   if (file.read(&ruleCount, sizeof(ruleCount)) != sizeof(ruleCount)) {
+    file.close();
     return false;
   }
 
@@ -613,6 +674,7 @@ bool CssParser::loadFromCache(FsFile& file) {
     uint16_t selectorLen = 0;
     if (file.read(&selectorLen, sizeof(selectorLen)) != sizeof(selectorLen)) {
       rulesBySelector_.clear();
+      file.close();
       return false;
     }
 
@@ -620,6 +682,7 @@ bool CssParser::loadFromCache(FsFile& file) {
     selector.resize(selectorLen);
     if (file.read(&selector[0], selectorLen) != selectorLen) {
       rulesBySelector_.clear();
+      file.close();
       return false;
     }
 
@@ -629,24 +692,28 @@ bool CssParser::loadFromCache(FsFile& file) {
 
     if (file.read(&enumVal, 1) != 1) {
       rulesBySelector_.clear();
+      file.close();
       return false;
     }
     style.textAlign = static_cast<CssTextAlign>(enumVal);
 
     if (file.read(&enumVal, 1) != 1) {
       rulesBySelector_.clear();
+      file.close();
       return false;
     }
     style.fontStyle = static_cast<CssFontStyle>(enumVal);
 
     if (file.read(&enumVal, 1) != 1) {
       rulesBySelector_.clear();
+      file.close();
       return false;
     }
     style.fontWeight = static_cast<CssFontWeight>(enumVal);
 
     if (file.read(&enumVal, 1) != 1) {
       rulesBySelector_.clear();
+      file.close();
       return false;
     }
     style.textDecoration = static_cast<CssTextDecoration>(enumVal);
@@ -668,6 +735,7 @@ bool CssParser::loadFromCache(FsFile& file) {
         !readLength(style.marginLeft) || !readLength(style.marginRight) || !readLength(style.paddingTop) ||
         !readLength(style.paddingBottom) || !readLength(style.paddingLeft) || !readLength(style.paddingRight)) {
       rulesBySelector_.clear();
+      file.close();
       return false;
     }
 
@@ -675,6 +743,7 @@ bool CssParser::loadFromCache(FsFile& file) {
     uint16_t definedBits = 0;
     if (file.read(&definedBits, sizeof(definedBits)) != sizeof(definedBits)) {
       rulesBySelector_.clear();
+      file.close();
       return false;
     }
     style.defined.textAlign = (definedBits & 1 << 0) != 0;
@@ -695,5 +764,6 @@ bool CssParser::loadFromCache(FsFile& file) {
   }
 
   LOG_DBG("CSS", "Loaded %u rules from cache", ruleCount);
+  file.close();
   return true;
 }

lib/Epub/Epub/css/CssParser.h

@@ -4,6 +4,7 @@
 
 #include <string>
 #include <unordered_map>
+#include <utility>
 #include <vector>
 
 #include "CssStyle.h"
@@ -29,7 +30,7 @@
  */
 class CssParser {
  public:
-  CssParser() = default;
+  explicit CssParser(std::string cachePath) : cachePath(std::move(cachePath)) {}
   ~CssParser() = default;
 
   // Non-copyable
@@ -76,28 +77,35 @@ class CssParser {
    */
   void clear() { rulesBySelector_.clear(); }
 
+  /**
+   * Check if CSS rules cache file exists
+   */
+  bool hasCache() const;
+
   /**
    * Save parsed CSS rules to a cache file.
-   * @param file Open file handle to write to
    * @return true if cache was written successfully
    */
-  bool saveToCache(FsFile& file) const;
+  bool saveToCache() const;
 
   /**
    * Load CSS rules from a cache file.
    * Clears any existing rules before loading.
-   * @param file Open file handle to read from
    * @return true if cache was loaded successfully
    */
-  bool loadFromCache(FsFile& file);
+  bool loadFromCache();
 
  private:
   // Storage: maps normalized selector -> style properties
   std::unordered_map<std::string, CssStyle> rulesBySelector_;
 
+  std::string cachePath;
+
   // Internal parsing helpers
-  void processRuleBlock(const std::string& selectorGroup, const std::string& declarations);
+  void processRuleBlockWithStyle(const std::string& selectorGroup, const CssStyle& style);
   static CssStyle parseDeclarations(const std::string& declBlock);
+  static void parseDeclarationIntoStyle(const std::string& decl, CssStyle& style, std::string& propNameBuf,
+                                        std::string& propValueBuf);
 
   // Individual property value parsers
   static CssTextAlign interpretAlignment(const std::string& val);
@@ -105,10 +113,10 @@ class CssParser {
   static CssFontWeight interpretFontWeight(const std::string& val);
   static CssTextDecoration interpretDecoration(const std::string& val);
   static CssLength interpretLength(const std::string& val);
-  static int8_t interpretSpacing(const std::string& val);
 
   // String utilities
   static std::string normalized(const std::string& s);
+  static void normalizedInto(const std::string& s, std::string& out);
   static std::vector<std::string> splitOnChar(const std::string& s, char delimiter);
   static std::vector<std::string> splitWhitespace(const std::string& s);
 };

lib/Epub/Epub/css/CssStyle.h

@@ -69,6 +69,7 @@ struct CssPropertyFlags {
   uint16_t paddingBottom : 1;
   uint16_t paddingLeft : 1;
   uint16_t paddingRight : 1;
+  uint16_t width : 1;
 
   CssPropertyFlags()
       : textAlign(0),
@@ -83,17 +84,19 @@ struct CssPropertyFlags {
         paddingTop(0),
         paddingBottom(0),
         paddingLeft(0),
-        paddingRight(0) {}
+        paddingRight(0),
+        width(0) {}
 
   [[nodiscard]] bool anySet() const {
     return textAlign || fontStyle || fontWeight || textDecoration || textIndent || marginTop || marginBottom ||
-           marginLeft || marginRight || paddingTop || paddingBottom || paddingLeft || paddingRight;
+           marginLeft || marginRight || paddingTop || paddingBottom || paddingLeft || paddingRight || width;
   }
 
   void clearAll() {
     textAlign = fontStyle = fontWeight = textDecoration = textIndent = 0;
     marginTop = marginBottom = marginLeft = marginRight = 0;
     paddingTop = paddingBottom = paddingLeft = paddingRight = 0;
+    width = 0;
   }
 };
 
@@ -115,6 +118,7 @@ struct CssStyle {
   CssLength paddingBottom;  // Padding after
   CssLength paddingLeft;    // Padding left
   CssLength paddingRight;   // Padding right
+  CssLength width;           // Element width (used for table columns/cells)
 
   CssPropertyFlags defined;  // Tracks which properties were explicitly set
 
@@ -173,6 +177,10 @@ struct CssStyle {
       paddingRight = base.paddingRight;
       defined.paddingRight = 1;
     }
+    if (base.hasWidth()) {
+      width = base.width;
+      defined.width = 1;
+    }
   }
 
   [[nodiscard]] bool hasTextAlign() const { return defined.textAlign; }
@@ -188,6 +196,7 @@ struct CssStyle {
   [[nodiscard]] bool hasPaddingBottom() const { return defined.paddingBottom; }
   [[nodiscard]] bool hasPaddingLeft() const { return defined.paddingLeft; }
   [[nodiscard]] bool hasPaddingRight() const { return defined.paddingRight; }
+  [[nodiscard]] bool hasWidth() const { return defined.width; }
 
   void reset() {
     textAlign = CssTextAlign::Left;
@@ -197,6 +206,7 @@ struct CssStyle {
     textIndent = CssLength{};
     marginTop = marginBottom = marginLeft = marginRight = CssLength{};
     paddingTop = paddingBottom = paddingLeft = paddingRight = CssLength{};
+    width = CssLength{};
     defined.clearAll();
   }
 };

lib/Epub/Epub/parsers/ChapterHtmlSlimParser.cpp

@@ -1,11 +1,17 @@
 #include "ChapterHtmlSlimParser.h"
 
+#include <FsHelpers.h>
 #include <GfxRenderer.h>
 #include <HalStorage.h>
 #include <Logging.h>
 #include <expat.h>
 
+#include <algorithm>
+
+#include "../../Epub.h"
 #include "../Page.h"
+#include "../converters/ImageDecoderFactory.h"
+#include "../converters/ImageToFramebufferDecoder.h"
 #include "../htmlEntities.h"
 
 const char* HEADER_TAGS[] = {"h1", "h2", "h3", "h4", "h5", "h6"};
@@ -32,8 +38,30 @@ constexpr int NUM_IMAGE_TAGS = sizeof(IMAGE_TAGS) / sizeof(IMAGE_TAGS[0]);
 const char* SKIP_TAGS[] = {"head"};
 constexpr int NUM_SKIP_TAGS = sizeof(SKIP_TAGS) / sizeof(SKIP_TAGS[0]);
 
+// Table tags that are transparent containers (just depth tracking, no special handling)
+const char* TABLE_TRANSPARENT_TAGS[] = {"thead", "tbody", "tfoot", "colgroup"};
+constexpr int NUM_TABLE_TRANSPARENT_TAGS = sizeof(TABLE_TRANSPARENT_TAGS) / sizeof(TABLE_TRANSPARENT_TAGS[0]);
+
+// Table tags to skip entirely (their children produce no useful output)
+const char* TABLE_SKIP_TAGS[] = {"caption"};
+constexpr int NUM_TABLE_SKIP_TAGS = sizeof(TABLE_SKIP_TAGS) / sizeof(TABLE_SKIP_TAGS[0]);
+
 bool isWhitespace(const char c) { return c == ' ' || c == '\r' || c == '\n' || c == '\t'; }
 
+// Parse an HTML width attribute value into a CssLength.
+// "200" -> 200px, "50%" -> 50 percent. Returns false if the value can't be parsed.
+static bool parseHtmlWidthAttr(const char* value, CssLength& out) {
+  char* end = nullptr;
+  const float num = strtof(value, &end);
+  if (end == value || num < 0) return false;
+  if (*end == '%') {
+    out = CssLength(num, CssUnit::Percent);
+  } else {
+    out = CssLength(num, CssUnit::Pixels);
+  }
+  return true;
+}
+
 // given the start and end of a tag, check to see if it matches a known tag
 bool matches(const char* tag_name, const char* possible_tags[], const int possible_tag_count) {
   for (int i = 0; i < possible_tag_count; i++) {
@@ -91,13 +119,37 @@ void ChapterHtmlSlimParser::flushPartWordBuffer() {
 
   // flush the buffer
   partWordBuffer[partWordBufferIndex] = '\0';
-  currentTextBlock->addWord(partWordBuffer, fontStyle, false, nextWordContinues);
+
+  // Handle double-encoded &nbsp; entities (e.g. &amp;nbsp; in source -> literal "&nbsp;" after
+  // XML parsing). Common in Wikipedia and other generated EPUBs. Replace with a space so the text
+  // renders cleanly. The space stays within the word, preserving non-breaking behavior.
+  std::string flushedWord(partWordBuffer);
+  size_t entityPos = 0;
+  while ((entityPos = flushedWord.find("&nbsp;", entityPos)) != std::string::npos) {
+    flushedWord.replace(entityPos, 6, " ");
+    entityPos += 1;
+  }
+
+  currentTextBlock->addWord(flushedWord, fontStyle, false, nextWordContinues);
   partWordBufferIndex = 0;
   nextWordContinues = false;
 }
 
 // start a new text block if needed
 void ChapterHtmlSlimParser::startNewTextBlock(const BlockStyle& blockStyle) {
+  // When inside a table cell, don't lay out to the page -- insert a forced line break
+  // within the cell's ParsedText so that block elements (p, div, br) create visual breaks.
+  if (inTable) {
+    if (partWordBufferIndex > 0) {
+      flushPartWordBuffer();
+    }
+    if (currentTextBlock && !currentTextBlock->isEmpty()) {
+      currentTextBlock->addLineBreak();
+    }
+    nextWordContinues = false;
+    return;
+  }
+
   nextWordContinues = false;  // New block = new paragraph, no continuation
   if (currentTextBlock) {
     // already have a text block running and it is empty - just reuse it
@@ -140,46 +192,304 @@ void XMLCALL ChapterHtmlSlimParser::startElement(void* userData, const XML_Char*
   centeredBlockStyle.textAlignDefined = true;
   centeredBlockStyle.alignment = CssTextAlign::Center;
 
-  // Special handling for tables - show placeholder text instead of dropping silently
+  // --- Table handling ---
   if (strcmp(name, "table") == 0) {
-    // Add placeholder text
-    self->startNewTextBlock(centeredBlockStyle);
+    if (self->inTable) {
+      // Nested table: skip it entirely for v1
+      self->skipUntilDepth = self->depth;
+      self->depth += 1;
+      return;
+    }
+
+    // Flush any pending content before the table
+    if (self->currentTextBlock && !self->currentTextBlock->isEmpty()) {
+      self->makePages();
+    }
+
+    self->inTable = true;
+    self->tableData.reset(new TableData());
+
+    // Create a safe empty currentTextBlock so character data outside cells
+    // (e.g. whitespace between tags) doesn't crash
+    auto tableBlockStyle = BlockStyle();
+    tableBlockStyle.alignment = CssTextAlign::Left;
+    self->currentTextBlock.reset(new ParsedText(self->extraParagraphSpacing, self->hyphenationEnabled, tableBlockStyle));
 
-    self->italicUntilDepth = min(self->italicUntilDepth, self->depth);
-    // Advance depth before processing character data (like you would for an element with text)
     self->depth += 1;
-    self->characterData(userData, "[Table omitted]", strlen("[Table omitted]"));
-
-    // Skip table contents (skip until parent as we pre-advanced depth above)
-    self->skipUntilDepth = self->depth - 1;
     return;
   }
 
-  if (matches(name, IMAGE_TAGS, NUM_IMAGE_TAGS)) {
-    // TODO: Start processing image tags
-    std::string alt = "[Image]";
-    if (atts != nullptr) {
-      for (int i = 0; atts[i]; i += 2) {
-        if (strcmp(atts[i], "alt") == 0) {
-          if (strlen(atts[i + 1]) > 0) {
-            alt = "[Image: " + std::string(atts[i + 1]) + "]";
-          }
-          break;
-        }
-      }
+  // Table structure tags (only when inside a table)
+  if (self->inTable) {
+    if (strcmp(name, "tr") == 0) {
+      self->tableData->rows.push_back(TableRow());
+      self->depth += 1;
+      return;
     }
 
-    LOG_DBG("EHP", "Image alt: %s", alt.c_str());
+    // <col> — capture width hint for column sizing
+    if (strcmp(name, "col") == 0) {
+      CssLength widthHint;
+      bool hasHint = false;
 
-    self->startNewTextBlock(centeredBlockStyle);
-    self->italicUntilDepth = min(self->italicUntilDepth, self->depth);
-    // Advance depth before processing character data (like you would for an element with text)
-    self->depth += 1;
-    self->characterData(userData, alt.c_str(), alt.length());
+      // Parse HTML width attribute
+      if (atts != nullptr) {
+        for (int i = 0; atts[i]; i += 2) {
+          if (strcmp(atts[i], "width") == 0) {
+            hasHint = parseHtmlWidthAttr(atts[i + 1], widthHint);
+            break;
+          }
+        }
+      }
 
-    // Skip table contents (skip until parent as we pre-advanced depth above)
-    self->skipUntilDepth = self->depth - 1;
-    return;
+      // CSS width (inline style) overrides HTML attribute
+      if (self->cssParser) {
+        std::string styleAttr;
+        if (atts != nullptr) {
+          for (int i = 0; atts[i]; i += 2) {
+            if (strcmp(atts[i], "style") == 0) {
+              styleAttr = atts[i + 1];
+              break;
+            }
+          }
+        }
+        if (!styleAttr.empty()) {
+          CssStyle inlineStyle = CssParser::parseInlineStyle(styleAttr);
+          if (inlineStyle.hasWidth()) {
+            widthHint = inlineStyle.width;
+            hasHint = true;
+          }
+        }
+      }
+
+      if (hasHint) {
+        self->tableData->colWidthHints.push_back(widthHint);
+      } else {
+        // Push a zero-value placeholder to maintain index alignment
+        self->tableData->colWidthHints.push_back(CssLength());
+      }
+
+      self->depth += 1;
+      return;
+    }
+
+    if (strcmp(name, "td") == 0 || strcmp(name, "th") == 0) {
+      const bool isHeader = strcmp(name, "th") == 0;
+
+      // Parse colspan and width attributes
+      int colspan = 1;
+      CssLength cellWidthHint;
+      bool hasCellWidthHint = false;
+      std::string cellStyleAttr;
+
+      if (atts != nullptr) {
+        for (int i = 0; atts[i]; i += 2) {
+          if (strcmp(atts[i], "colspan") == 0) {
+            colspan = atoi(atts[i + 1]);
+            if (colspan < 1) colspan = 1;
+          } else if (strcmp(atts[i], "width") == 0) {
+            hasCellWidthHint = parseHtmlWidthAttr(atts[i + 1], cellWidthHint);
+          } else if (strcmp(atts[i], "style") == 0) {
+            cellStyleAttr = atts[i + 1];
+          }
+        }
+      }
+
+      // CSS width (inline style or stylesheet) overrides HTML attribute
+      if (self->cssParser) {
+        std::string classAttr;
+        if (atts != nullptr) {
+          for (int i = 0; atts[i]; i += 2) {
+            if (strcmp(atts[i], "class") == 0) {
+              classAttr = atts[i + 1];
+              break;
+            }
+          }
+        }
+        CssStyle cellCssStyle = self->cssParser->resolveStyle(name, classAttr);
+        if (!cellStyleAttr.empty()) {
+          CssStyle inlineStyle = CssParser::parseInlineStyle(cellStyleAttr);
+          cellCssStyle.applyOver(inlineStyle);
+        }
+        if (cellCssStyle.hasWidth()) {
+          cellWidthHint = cellCssStyle.width;
+          hasCellWidthHint = true;
+        }
+      }
+
+      // Ensure there's a row to add cells to
+      if (self->tableData->rows.empty()) {
+        self->tableData->rows.push_back(TableRow());
+      }
+
+      // Create a new ParsedText for this cell (characterData will flow into it)
+      auto cellBlockStyle = BlockStyle();
+      cellBlockStyle.alignment = CssTextAlign::Left;
+      cellBlockStyle.textAlignDefined = true;
+      // Explicitly disable paragraph indent for table cells
+      cellBlockStyle.textIndent = 0;
+      cellBlockStyle.textIndentDefined = true;
+      self->currentTextBlock.reset(
+          new ParsedText(self->extraParagraphSpacing, self->hyphenationEnabled, cellBlockStyle));
+      self->nextWordContinues = false;
+
+      // Track the cell
+      auto& currentRow = self->tableData->rows.back();
+      currentRow.cells.push_back(TableCell());
+      currentRow.cells.back().isHeader = isHeader;
+      currentRow.cells.back().colspan = colspan;
+      if (hasCellWidthHint) {
+        currentRow.cells.back().widthHint = cellWidthHint;
+        currentRow.cells.back().hasWidthHint = true;
+      }
+
+      // Apply bold for header cells
+      if (isHeader) {
+        self->boldUntilDepth = std::min(self->boldUntilDepth, self->depth);
+        self->updateEffectiveInlineStyle();
+      }
+
+      self->depth += 1;
+      return;
+    }
+
+    // Transparent table container tags
+    if (matches(name, TABLE_TRANSPARENT_TAGS, NUM_TABLE_TRANSPARENT_TAGS)) {
+      self->depth += 1;
+      return;
+    }
+
+    // Skip colgroup, col, caption
+    if (matches(name, TABLE_SKIP_TAGS, NUM_TABLE_SKIP_TAGS)) {
+      self->skipUntilDepth = self->depth;
+      self->depth += 1;
+      return;
+    }
+
+    // Other tags inside table cells (p, div, span, b, i, etc.) fall through
+    // to the normal handling below. startNewTextBlock is a no-op when inTable.
+  }
+
+  if (matches(name, IMAGE_TAGS, NUM_IMAGE_TAGS)) {
+    std::string src;
+    std::string alt;
+    if (atts != nullptr) {
+      for (int i = 0; atts[i]; i += 2) {
+        if (strcmp(atts[i], "src") == 0) {
+          src = atts[i + 1];
+        } else if (strcmp(atts[i], "alt") == 0) {
+          alt = atts[i + 1];
+        }
+      }
+
+      if (!src.empty()) {
+        LOG_DBG("EHP", "Found image: src=%s", src.c_str());
+
+        {
+          // Resolve the image path relative to the HTML file
+          std::string resolvedPath = FsHelpers::normalisePath(self->contentBase + src);
+
+          // Create a unique filename for the cached image
+          std::string ext;
+          size_t extPos = resolvedPath.rfind('.');
+          if (extPos != std::string::npos) {
+            ext = resolvedPath.substr(extPos);
+          }
+          std::string cachedImagePath = self->imageBasePath + std::to_string(self->imageCounter++) + ext;
+
+          // Extract image to cache file
+          FsFile cachedImageFile;
+          bool extractSuccess = false;
+          if (Storage.openFileForWrite("EHP", cachedImagePath, cachedImageFile)) {
+            extractSuccess = self->epub->readItemContentsToStream(resolvedPath, cachedImageFile, 4096);
+            cachedImageFile.flush();
+            cachedImageFile.close();
+            delay(50);  // Give SD card time to sync
+          }
+
+          if (extractSuccess) {
+            // Get image dimensions
+            ImageDimensions dims = {0, 0};
+            ImageToFramebufferDecoder* decoder = ImageDecoderFactory::getDecoder(cachedImagePath);
+            if (decoder && decoder->getDimensions(cachedImagePath, dims)) {
+              LOG_DBG("EHP", "Image dimensions: %dx%d", dims.width, dims.height);
+
+              // Scale to fit viewport while maintaining aspect ratio
+              int maxWidth = self->viewportWidth;
+              int maxHeight = self->viewportHeight;
+              float scaleX = (dims.width > maxWidth) ? (float)maxWidth / dims.width : 1.0f;
+              float scaleY = (dims.height > maxHeight) ? (float)maxHeight / dims.height : 1.0f;
+              float scale = (scaleX < scaleY) ? scaleX : scaleY;
+              if (scale > 1.0f) scale = 1.0f;
+
+              int displayWidth = (int)(dims.width * scale);
+              int displayHeight = (int)(dims.height * scale);
+
+              LOG_DBG("EHP", "Display size: %dx%d (scale %.2f)", displayWidth, displayHeight, scale);
+
+              // Create page for image - only break if image won't fit remaining space
+              if (self->currentPage && !self->currentPage->elements.empty() &&
+                  (self->currentPageNextY + displayHeight > self->viewportHeight)) {
+                self->completePageFn(std::move(self->currentPage));
+                self->currentPage.reset(new Page());
+                if (!self->currentPage) {
+                  LOG_ERR("EHP", "Failed to create new page");
+                  return;
+                }
+                self->currentPageNextY = 0;
+              } else if (!self->currentPage) {
+                self->currentPage.reset(new Page());
+                if (!self->currentPage) {
+                  LOG_ERR("EHP", "Failed to create initial page");
+                  return;
+                }
+                self->currentPageNextY = 0;
+              }
+
+              // Create ImageBlock and add to page
+              auto imageBlock = std::make_shared<ImageBlock>(cachedImagePath, displayWidth, displayHeight);
+              if (!imageBlock) {
+                LOG_ERR("EHP", "Failed to create ImageBlock");
+                return;
+              }
+              int xPos = (self->viewportWidth - displayWidth) / 2;
+              auto pageImage = std::make_shared<PageImage>(imageBlock, xPos, self->currentPageNextY);
+              if (!pageImage) {
+                LOG_ERR("EHP", "Failed to create PageImage");
+                return;
+              }
+              self->currentPage->elements.push_back(pageImage);
+              self->currentPageNextY += displayHeight;
+
+              self->depth += 1;
+              return;
+            } else {
+              LOG_ERR("EHP", "Failed to get image dimensions");
+              Storage.remove(cachedImagePath.c_str());
+            }
+          } else {
+            LOG_ERR("EHP", "Failed to extract image");
+          }
+        }
+      }
+
+      // Fallback to alt text if image processing fails
+      if (!alt.empty()) {
+        alt = "[Image: " + alt + "]";
+        self->startNewTextBlock(centeredBlockStyle);
+        self->italicUntilDepth = std::min(self->italicUntilDepth, self->depth);
+        self->depth += 1;
+        self->characterData(userData, alt.c_str(), alt.length());
+        // Skip any child content (skip until parent as we pre-advanced depth above)
+        self->skipUntilDepth = self->depth - 1;
+        return;
+      }
+
+      // No alt text, skip
+      self->skipUntilDepth = self->depth;
+      self->depth += 1;
+      return;
+    }
   }
 
   if (matches(name, SKIP_TAGS, NUM_SKIP_TAGS)) {
@@ -408,7 +718,8 @@ void XMLCALL ChapterHtmlSlimParser::characterData(void* userData, const XML_Char
   // There should be enough here to build out 1-2 full pages and doing this will free up a lot of
   // memory.
   // Spotted when reading Intermezzo, there are some really long text blocks in there.
-  if (self->currentTextBlock->size() > 750) {
+  // Skip this when inside a table - cell content is buffered for later layout.
+  if (!self->inTable && self->currentTextBlock->size() > 750) {
     LOG_DBG("EHP", "Text block too long, splitting into multiple pages");
     self->currentTextBlock->layoutAndExtractLines(
         self->renderer, self->fontId, self->viewportWidth,
@@ -446,15 +757,17 @@ void XMLCALL ChapterHtmlSlimParser::endElement(void* userData, const XML_Char* n
 
   const bool styleWillChange = willPopStyleStack || willClearBold || willClearItalic || willClearUnderline;
   const bool headerOrBlockTag = isHeaderOrBlock(name);
+  const bool isTableCellTag = strcmp(name, "td") == 0 || strcmp(name, "th") == 0;
+  const bool isTableTag = strcmp(name, "table") == 0;
 
   // Flush buffer with current style BEFORE any style changes
   if (self->partWordBufferIndex > 0) {
     // Flush if style will change OR if we're closing a block/structural element
-    const bool isInlineTag = !headerOrBlockTag && strcmp(name, "table") != 0 &&
+    const bool isInlineTag = !headerOrBlockTag && !isTableTag && !isTableCellTag &&
                              !matches(name, IMAGE_TAGS, NUM_IMAGE_TAGS) && self->depth != 1;
     const bool shouldFlush = styleWillChange || headerOrBlockTag || matches(name, BOLD_TAGS, NUM_BOLD_TAGS) ||
                              matches(name, ITALIC_TAGS, NUM_ITALIC_TAGS) ||
-                             matches(name, UNDERLINE_TAGS, NUM_UNDERLINE_TAGS) || strcmp(name, "table") == 0 ||
+                             matches(name, UNDERLINE_TAGS, NUM_UNDERLINE_TAGS) || isTableTag || isTableCellTag ||
                              matches(name, IMAGE_TAGS, NUM_IMAGE_TAGS) || self->depth == 1;
 
     if (shouldFlush) {
@@ -466,6 +779,57 @@ void XMLCALL ChapterHtmlSlimParser::endElement(void* userData, const XML_Char* n
     }
   }
 
+  // --- Table cell/row/table close handling ---
+  if (self->inTable) {
+    if (isTableCellTag) {
+      // Save the current cell content into the table data
+      if (self->tableData && !self->tableData->rows.empty()) {
+        auto& currentRow = self->tableData->rows.back();
+        if (!currentRow.cells.empty()) {
+          currentRow.cells.back().content = std::move(self->currentTextBlock);
+        }
+      }
+
+      // Create a safe empty ParsedText so character data between cells doesn't crash
+      auto safeBlockStyle = BlockStyle();
+      safeBlockStyle.alignment = CssTextAlign::Left;
+      self->currentTextBlock.reset(
+          new ParsedText(self->extraParagraphSpacing, self->hyphenationEnabled, safeBlockStyle));
+      self->nextWordContinues = false;
+    }
+
+    if (isTableTag) {
+      // Process the entire buffered table
+      self->depth -= 1;
+
+      // Clean up style state for this depth
+      if (self->skipUntilDepth == self->depth) self->skipUntilDepth = INT_MAX;
+      if (self->boldUntilDepth == self->depth) self->boldUntilDepth = INT_MAX;
+      if (self->italicUntilDepth == self->depth) self->italicUntilDepth = INT_MAX;
+      if (self->underlineUntilDepth == self->depth) self->underlineUntilDepth = INT_MAX;
+      if (!self->inlineStyleStack.empty() && self->inlineStyleStack.back().depth == self->depth) {
+        self->inlineStyleStack.pop_back();
+        self->updateEffectiveInlineStyle();
+      }
+
+      self->processTable();
+
+      self->inTable = false;
+      self->tableData.reset();
+
+      // Restore a fresh text block for content after the table
+      auto paragraphAlignmentBlockStyle = BlockStyle();
+      paragraphAlignmentBlockStyle.textAlignDefined = true;
+      const auto align = (self->paragraphAlignment == static_cast<uint8_t>(CssTextAlign::None))
+                             ? CssTextAlign::Justify
+                             : static_cast<CssTextAlign>(self->paragraphAlignment);
+      paragraphAlignmentBlockStyle.alignment = align;
+      self->currentTextBlock.reset(
+          new ParsedText(self->extraParagraphSpacing, self->hyphenationEnabled, paragraphAlignmentBlockStyle));
+      return;  // depth already decremented, skip the normal endElement cleanup
+    }
+  }
+
   self->depth -= 1;
 
   // Leaving skip
@@ -653,3 +1017,335 @@ void ChapterHtmlSlimParser::makePages() {
     currentPageNextY += lineHeight / 2;
   }
 }
+
+// ---------------------------------------------------------------------------
+// Table processing
+// ---------------------------------------------------------------------------
+
+// Cell padding in pixels (horizontal space between grid line and cell text)
+static constexpr int TABLE_CELL_PAD_X = 4;
+// Vertical cell padding — asymmetric because font metrics include internal leading (whitespace
+// above glyphs), so the top already has built-in visual space. Less explicit padding on top,
+// more on bottom, produces visually balanced results.
+static constexpr int TABLE_CELL_PAD_TOP = 1;
+static constexpr int TABLE_CELL_PAD_BOTTOM = 3;
+// Minimum usable column width in pixels (below this text is unreadable)
+static constexpr int TABLE_MIN_COL_WIDTH = 30;
+// Grid line width in pixels
+static constexpr int TABLE_GRID_LINE_PX = 1;
+
+void ChapterHtmlSlimParser::addTableRowToPage(std::shared_ptr<PageTableRow> row) {
+  if (!currentPage) {
+    currentPage.reset(new Page());
+    currentPageNextY = 0;
+  }
+
+  const int16_t rowH = row->getHeight();
+
+  // If this row doesn't fit on the current page, start a new one
+  if (currentPageNextY + rowH > viewportHeight) {
+    completePageFn(std::move(currentPage));
+    currentPage.reset(new Page());
+    currentPageNextY = 0;
+  }
+
+  row->xPos = 0;
+  row->yPos = currentPageNextY;
+  currentPage->elements.push_back(std::move(row));
+  currentPageNextY += rowH;
+}
+
+void ChapterHtmlSlimParser::processTable() {
+  if (!tableData || tableData->rows.empty()) {
+    return;
+  }
+
+  if (!currentPage) {
+    currentPage.reset(new Page());
+    currentPageNextY = 0;
+  }
+
+  const int lh = static_cast<int>(renderer.getLineHeight(fontId) * lineCompression);
+
+  // 1. Determine logical column count using colspan.
+  //    Each cell occupies cell.colspan logical columns. The total for a row is the sum of colspans.
+  size_t numCols = 0;
+  for (const auto& row : tableData->rows) {
+    size_t rowLogicalCols = 0;
+    for (const auto& cell : row.cells) {
+      rowLogicalCols += static_cast<size_t>(cell.colspan);
+    }
+    numCols = std::max(numCols, rowLogicalCols);
+  }
+
+  if (numCols == 0) {
+    return;
+  }
+
+  // 2. Measure natural width of each cell and compute per-column max natural width.
+  //    Only non-spanning cells (colspan==1) contribute to individual column widths.
+  //    Spanning cells use the combined width of their spanned columns.
+  std::vector<uint16_t> colNaturalWidth(numCols, 0);
+
+  for (const auto& row : tableData->rows) {
+    size_t logicalCol = 0;
+    for (const auto& cell : row.cells) {
+      if (cell.colspan == 1 && cell.content && !cell.content->isEmpty()) {
+        if (logicalCol < numCols) {
+          const uint16_t w = cell.content->getNaturalWidth(renderer, fontId);
+          if (w > colNaturalWidth[logicalCol]) {
+            colNaturalWidth[logicalCol] = w;
+          }
+        }
+      }
+      logicalCol += static_cast<size_t>(cell.colspan);
+    }
+  }
+
+  // 3. Calculate column widths to fit viewport.
+  //    Available width = viewport - outer borders - internal column borders - cell padding
+  const int totalGridLines = static_cast<int>(numCols) + 1;  // left + between columns + right
+  const int totalPadding = static_cast<int>(numCols) * TABLE_CELL_PAD_X * 2;
+  const int availableForContent = viewportWidth - totalGridLines * TABLE_GRID_LINE_PX - totalPadding;
+
+  // 3a. Resolve width hints per column.
+  //     Priority: <col> hints > max cell hint (colspan=1 only).
+  //     Percentages are relative to availableForContent.
+  const float emSize = static_cast<float>(lh);
+  const float containerW = static_cast<float>(std::max(availableForContent, 0));
+
+  std::vector<int> colHintedWidth(numCols, -1);  // -1 = no hint
+
+  // From <col> tags
+  for (size_t c = 0; c < numCols && c < tableData->colWidthHints.size(); ++c) {
+    const auto& hint = tableData->colWidthHints[c];
+    if (hint.value > 0) {
+      int px = static_cast<int>(hint.toPixels(emSize, containerW));
+      if (px > 0) {
+        colHintedWidth[c] = std::max(px, TABLE_MIN_COL_WIDTH);
+      }
+    }
+  }
+
+  // From <td>/<th> cell width hints (only override if no <col> hint exists for this column)
+  for (const auto& row : tableData->rows) {
+    size_t logicalCol = 0;
+    for (const auto& cell : row.cells) {
+      if (cell.colspan == 1 && cell.hasWidthHint && logicalCol < numCols) {
+        if (colHintedWidth[logicalCol] < 0) {  // no <col> hint yet
+          int px = static_cast<int>(cell.widthHint.toPixels(emSize, containerW));
+          if (px > colHintedWidth[logicalCol]) {
+            colHintedWidth[logicalCol] = std::max(px, TABLE_MIN_COL_WIDTH);
+          }
+        }
+      }
+      logicalCol += static_cast<size_t>(cell.colspan);
+    }
+  }
+
+  // 3b. Distribute column widths: hinted columns get their hint, unhinted use auto-sizing.
+  std::vector<uint16_t> colWidths(numCols, 0);
+
+  if (availableForContent <= 0) {
+    const uint16_t equalWidth = static_cast<uint16_t>(viewportWidth / numCols);
+    for (size_t c = 0; c < numCols; ++c) {
+      colWidths[c] = equalWidth;
+    }
+  } else {
+    // First, assign hinted columns and track how much space they consume
+    int hintedSpaceUsed = 0;
+    size_t unhintedCount = 0;
+    for (size_t c = 0; c < numCols; ++c) {
+      if (colHintedWidth[c] > 0) {
+        hintedSpaceUsed += colHintedWidth[c];
+      } else {
+        unhintedCount++;
+      }
+    }
+
+    // If hinted columns exceed available space, scale them down proportionally
+    if (hintedSpaceUsed > availableForContent && hintedSpaceUsed > 0) {
+      for (size_t c = 0; c < numCols; ++c) {
+        if (colHintedWidth[c] > 0) {
+          colHintedWidth[c] = colHintedWidth[c] * availableForContent / hintedSpaceUsed;
+          colHintedWidth[c] = std::max(colHintedWidth[c], TABLE_MIN_COL_WIDTH);
+        }
+      }
+      // Recalculate
+      hintedSpaceUsed = 0;
+      for (size_t c = 0; c < numCols; ++c) {
+        if (colHintedWidth[c] > 0) {
+          hintedSpaceUsed += colHintedWidth[c];
+        }
+      }
+    }
+
+    // Assign hinted columns
+    for (size_t c = 0; c < numCols; ++c) {
+      if (colHintedWidth[c] > 0) {
+        colWidths[c] = static_cast<uint16_t>(colHintedWidth[c]);
+      }
+    }
+
+    // Distribute remaining space among unhinted columns using the existing algorithm
+    const int remainingForUnhinted = std::max(availableForContent - hintedSpaceUsed, 0);
+
+    if (unhintedCount > 0 && remainingForUnhinted > 0) {
+      // Compute total natural width of unhinted columns
+      int totalNaturalUnhinted = 0;
+      for (size_t c = 0; c < numCols; ++c) {
+        if (colHintedWidth[c] <= 0) {
+          totalNaturalUnhinted += colNaturalWidth[c];
+        }
+      }
+
+      if (totalNaturalUnhinted <= remainingForUnhinted) {
+        // All unhinted content fits — distribute extra space equally among unhinted columns
+        const int extraSpace = remainingForUnhinted - totalNaturalUnhinted;
+        const int perColExtra = extraSpace / static_cast<int>(unhintedCount);
+        for (size_t c = 0; c < numCols; ++c) {
+          if (colHintedWidth[c] <= 0) {
+            colWidths[c] = static_cast<uint16_t>(colNaturalWidth[c] + perColExtra);
+          }
+        }
+      } else {
+        // Unhinted content exceeds remaining space — two-pass fair-share among unhinted columns
+        const int equalShare = remainingForUnhinted / static_cast<int>(unhintedCount);
+
+        int spaceUsedByFitting = 0;
+        int naturalOfWide = 0;
+        size_t wideCount = 0;
+
+        for (size_t c = 0; c < numCols; ++c) {
+          if (colHintedWidth[c] <= 0) {
+            if (static_cast<int>(colNaturalWidth[c]) <= equalShare) {
+              colWidths[c] = colNaturalWidth[c];
+              spaceUsedByFitting += colNaturalWidth[c];
+            } else {
+              naturalOfWide += colNaturalWidth[c];
+              wideCount++;
+            }
+          }
+        }
+
+        const int wideSpace = remainingForUnhinted - spaceUsedByFitting;
+        for (size_t c = 0; c < numCols; ++c) {
+          if (colHintedWidth[c] <= 0 && static_cast<int>(colNaturalWidth[c]) > equalShare) {
+            if (naturalOfWide > 0 && wideCount > 1) {
+              int proportional = static_cast<int>(colNaturalWidth[c]) * wideSpace / naturalOfWide;
+              colWidths[c] = static_cast<uint16_t>(std::max(proportional, TABLE_MIN_COL_WIDTH));
+            } else {
+              colWidths[c] = static_cast<uint16_t>(std::max(wideSpace, TABLE_MIN_COL_WIDTH));
+            }
+          }
+        }
+      }
+    } else if (unhintedCount > 0) {
+      // No remaining space for unhinted columns — give them minimum width
+      for (size_t c = 0; c < numCols; ++c) {
+        if (colHintedWidth[c] <= 0) {
+          colWidths[c] = static_cast<uint16_t>(TABLE_MIN_COL_WIDTH);
+        }
+      }
+    }
+  }
+
+  // Compute column x-offsets (cumulative: border + padding + content width + padding + border ...)
+  std::vector<uint16_t> colXOffsets(numCols, 0);
+  int xAccum = TABLE_GRID_LINE_PX;  // start after left border
+  for (size_t c = 0; c < numCols; ++c) {
+    colXOffsets[c] = static_cast<uint16_t>(xAccum);
+    xAccum += TABLE_CELL_PAD_X + colWidths[c] + TABLE_CELL_PAD_X + TABLE_GRID_LINE_PX;
+  }
+  const int16_t totalTableWidth = static_cast<int16_t>(xAccum);
+
+  // Helper: compute the combined content width for a cell spanning multiple columns.
+  // This includes the content widths plus the internal grid lines and padding between spanned columns.
+  auto spanContentWidth = [&](size_t startCol, int colspan) -> uint16_t {
+    int width = 0;
+    for (int s = 0; s < colspan && startCol + s < numCols; ++s) {
+      width += colWidths[startCol + s];
+      if (s > 0) {
+        // Add internal padding and grid line between spanned columns
+        width += TABLE_CELL_PAD_X * 2 + TABLE_GRID_LINE_PX;
+      }
+    }
+    return static_cast<uint16_t>(std::max(width, 0));
+  };
+
+  // Helper: compute the full cell width (including padding on both sides) for a spanning cell.
+  auto spanFullCellWidth = [&](size_t startCol, int colspan) -> uint16_t {
+    if (colspan <= 0 || startCol >= numCols) return 0;
+    const size_t endCol = std::min(startCol + static_cast<size_t>(colspan), numCols) - 1;
+    // From the left edge of startCol's cell to the right edge of endCol's cell
+    const int leftEdge = colXOffsets[startCol];
+    const int rightEdge = colXOffsets[endCol] + TABLE_CELL_PAD_X + colWidths[endCol] + TABLE_CELL_PAD_X;
+    return static_cast<uint16_t>(rightEdge - leftEdge);
+  };
+
+  // 4. Lay out each row: map cells to logical columns, create PageTableRow
+  for (auto& row : tableData->rows) {
+    // Build cell data for this row, one entry per CELL (not per logical column).
+    // Each PageTableCellData gets the correct x-offset and combined column width.
+    std::vector<PageTableCellData> cellDataVec;
+    size_t maxLinesInRow = 1;
+    size_t logicalCol = 0;
+
+    for (size_t ci = 0; ci < row.cells.size() && logicalCol < numCols; ++ci) {
+      auto& cell = row.cells[ci];
+      const int cs = cell.colspan;
+
+      PageTableCellData cellData;
+      cellData.xOffset = colXOffsets[logicalCol];
+      cellData.columnWidth = spanFullCellWidth(logicalCol, cs);
+
+      if (cell.content && !cell.content->isEmpty()) {
+        // Center-align cells that span the full table width (common for section headers/titles)
+        if (cs >= static_cast<int>(numCols)) {
+          BlockStyle centeredStyle = cell.content->getBlockStyle();
+          centeredStyle.alignment = CssTextAlign::Center;
+          centeredStyle.textAlignDefined = true;
+          cell.content->setBlockStyle(centeredStyle);
+        }
+
+        const uint16_t contentWidth = spanContentWidth(logicalCol, cs);
+        std::vector<std::shared_ptr<TextBlock>> cellLines;
+
+        cell.content->layoutAndExtractLines(
+            renderer, fontId, contentWidth,
+            [&cellLines](const std::shared_ptr<TextBlock>& textBlock) { cellLines.push_back(textBlock); });
+
+        if (cellLines.size() > maxLinesInRow) {
+          maxLinesInRow = cellLines.size();
+        }
+        cellData.lines = std::move(cellLines);
+      }
+
+      cellDataVec.push_back(std::move(cellData));
+      logicalCol += static_cast<size_t>(cs);
+    }
+
+    // Fill remaining logical columns with empty cells (rows shorter than numCols)
+    while (logicalCol < numCols) {
+      PageTableCellData emptyCell;
+      emptyCell.xOffset = colXOffsets[logicalCol];
+      emptyCell.columnWidth = static_cast<uint16_t>(TABLE_CELL_PAD_X + colWidths[logicalCol] + TABLE_CELL_PAD_X);
+      cellDataVec.push_back(std::move(emptyCell));
+      logicalCol++;
+    }
+
+    // Row height = max lines * lineHeight + top/bottom border + asymmetric vertical padding
+    const int16_t rowHeight = static_cast<int16_t>(
+        static_cast<int>(maxLinesInRow) * lh + 2 + TABLE_CELL_PAD_TOP + TABLE_CELL_PAD_BOTTOM);
+
+    auto pageTableRow = std::make_shared<PageTableRow>(
+        std::move(cellDataVec), rowHeight, totalTableWidth, static_cast<int16_t>(lh), 0, 0);
+
+    addTableRowToPage(std::move(pageTableRow));
+  }
+
+  // Add a small gap after the table
+  if (extraParagraphSpacing) {
+    currentPageNextY += lh / 2;
+  }
+}

lib/Epub/Epub/parsers/ChapterHtmlSlimParser.h

@@ -7,16 +7,21 @@
 #include <memory>
 
 #include "../ParsedText.h"
+#include "../TableData.h"
+#include "../blocks/ImageBlock.h"
 #include "../blocks/TextBlock.h"
 #include "../css/CssParser.h"
 #include "../css/CssStyle.h"
 
 class Page;
+class PageTableRow;
 class GfxRenderer;
+class Epub;
 
 #define MAX_WORD_SIZE 200
 
 class ChapterHtmlSlimParser {
+  std::shared_ptr<Epub> epub;
   const std::string& filepath;
   GfxRenderer& renderer;
   std::function<void(std::unique_ptr<Page>)> completePageFn;
@@ -43,6 +48,9 @@ class ChapterHtmlSlimParser {
   bool hyphenationEnabled;
   const CssParser* cssParser;
   bool embeddedStyle;
+  std::string contentBase;
+  std::string imageBasePath;
+  int imageCounter = 0;
 
   // Style tracking (replaces depth-based approach)
   struct StyleStackEntry {
@@ -57,10 +65,16 @@ class ChapterHtmlSlimParser {
   bool effectiveItalic = false;
   bool effectiveUnderline = false;
 
+  // Table buffering state
+  bool inTable = false;
+  std::unique_ptr<TableData> tableData;
+
   void updateEffectiveInlineStyle();
   void startNewTextBlock(const BlockStyle& blockStyle);
   void flushPartWordBuffer();
   void makePages();
+  void processTable();
+  void addTableRowToPage(std::shared_ptr<PageTableRow> row);
   // XML callbacks
   static void XMLCALL startElement(void* userData, const XML_Char* name, const XML_Char** atts);
   static void XMLCALL characterData(void* userData, const XML_Char* s, int len);
@@ -68,15 +82,17 @@ class ChapterHtmlSlimParser {
   static void XMLCALL endElement(void* userData, const XML_Char* name);
 
  public:
-  explicit ChapterHtmlSlimParser(const std::string& filepath, GfxRenderer& renderer, const int fontId,
-                                 const float lineCompression, const bool extraParagraphSpacing,
+  explicit ChapterHtmlSlimParser(std::shared_ptr<Epub> epub, const std::string& filepath, GfxRenderer& renderer,
+                                 const int fontId, const float lineCompression, const bool extraParagraphSpacing,
                                  const uint8_t paragraphAlignment, const uint16_t viewportWidth,
                                  const uint16_t viewportHeight, const bool hyphenationEnabled,
                                  const std::function<void(std::unique_ptr<Page>)>& completePageFn,
-                                 const bool embeddedStyle, const std::function<void()>& popupFn = nullptr,
+                                 const bool embeddedStyle, const std::string& contentBase,
+                                 const std::string& imageBasePath, const std::function<void()>& popupFn = nullptr,
                                  const CssParser* cssParser = nullptr)
 
-      : filepath(filepath),
+      : epub(epub),
+        filepath(filepath),
         renderer(renderer),
         fontId(fontId),
         lineCompression(lineCompression),
@@ -88,7 +104,9 @@ class ChapterHtmlSlimParser {
         completePageFn(completePageFn),
         popupFn(popupFn),
         cssParser(cssParser),
-        embeddedStyle(embeddedStyle) {}
+        embeddedStyle(embeddedStyle),
+        contentBase(contentBase),
+        imageBasePath(imageBasePath) {}
 
   ~ChapterHtmlSlimParser() = default;
   bool parseAndBuildPages();

lib/GfxRenderer/GfxRenderer.cpp

@@ -726,6 +726,23 @@ void GfxRenderer::displayBuffer(const HalDisplay::RefreshMode refreshMode) const
   display.displayBuffer(refreshMode, fadingFix);
 }
 
+// EXPERIMENTAL: Display only a rectangular region with specified refresh mode
+void GfxRenderer::displayWindow(int x, int y, int width, int height,
+                                HalDisplay::RefreshMode mode) const {
+  LOG_DBG("GFX", "Displaying window at (%d,%d) size (%dx%d) with mode %d", x, y, width, height,
+          static_cast<int>(mode));
+
+  // Validate bounds
+  if (x < 0 || y < 0 || x + width > getScreenWidth() || y + height > getScreenHeight()) {
+    LOG_ERR("GFX", "Window bounds exceed display dimensions!");
+    return;
+  }
+
+  display.displayWindow(static_cast<uint16_t>(x), static_cast<uint16_t>(y),
+                        static_cast<uint16_t>(width), static_cast<uint16_t>(height), mode,
+                        fadingFix);
+}
+
 std::string GfxRenderer::truncatedText(const int fontId, const char* text, const int maxWidth,
                                        const EpdFontFamily::Style style) const {
   if (!text || maxWidth <= 0) return "";

lib/GfxRenderer/GfxRenderer.h

@@ -70,7 +70,8 @@ class GfxRenderer {
   int getScreenHeight() const;
   void displayBuffer(HalDisplay::RefreshMode refreshMode = HalDisplay::FAST_REFRESH) const;
   // EXPERIMENTAL: Windowed update - display only a rectangular region
-  // void displayWindow(int x, int y, int width, int height) const;
+  void displayWindow(int x, int y, int width, int height,
+                     HalDisplay::RefreshMode mode = HalDisplay::FAST_REFRESH) const;
   void invertScreen() const;
   void clearScreen(uint8_t color = 0xFF) const;
   void getOrientedViewableTRBL(int* outTop, int* outRight, int* outBottom, int* outLeft) const;
@@ -120,6 +121,7 @@ class GfxRenderer {
 
   // Grayscale functions
   void setRenderMode(const RenderMode mode) { this->renderMode = mode; }
+  RenderMode getRenderMode() const { return renderMode; }
   void copyGrayscaleLsbBuffers() const;
   void copyGrayscaleMsbBuffers() const;
   void displayGrayBuffer() const;

lib/hal/HalDisplay.cpp

@@ -32,6 +32,13 @@ void HalDisplay::displayBuffer(HalDisplay::RefreshMode mode, bool turnOffScreen)
   einkDisplay.displayBuffer(convertRefreshMode(mode), turnOffScreen);
 }
 
+// EXPERIMENTAL: Display only a rectangular region
+void HalDisplay::displayWindow(uint16_t x, uint16_t y, uint16_t w, uint16_t h,
+                               HalDisplay::RefreshMode mode, bool turnOffScreen) {
+  (void)mode;  // EInkDisplay::displayWindow does not take mode yet
+  einkDisplay.displayWindow(x, y, w, h, turnOffScreen);
+}
+
 void HalDisplay::refreshDisplay(HalDisplay::RefreshMode mode, bool turnOffScreen) {
   einkDisplay.refreshDisplay(convertRefreshMode(mode), turnOffScreen);
 }

lib/hal/HalDisplay.h

@@ -34,6 +34,10 @@ class HalDisplay {
   void displayBuffer(RefreshMode mode = RefreshMode::FAST_REFRESH, bool turnOffScreen = false);
   void refreshDisplay(RefreshMode mode = RefreshMode::FAST_REFRESH, bool turnOffScreen = false);
 
+  // EXPERIMENTAL: Display only a rectangular region
+  void displayWindow(uint16_t x, uint16_t y, uint16_t w, uint16_t h,
+                     RefreshMode mode = RefreshMode::FAST_REFRESH, bool turnOffScreen = false);
+
   // Power management
   void deepSleep();
 

lib/hal/HalPowerManager.cpp

@@ -17,14 +17,14 @@ void HalPowerManager::setPowerSaving(bool enabled) {
   if (enabled && !isLowPower) {
     LOG_DBG("PWR", "Going to low-power mode");
     if (!setCpuFrequencyMhz(LOW_POWER_FREQ)) {
-      LOG_ERR("PWR", "Failed to set low-power CPU frequency");
+      LOG_DBG("PWR", "Failed to set CPU frequency = %d MHz", LOW_POWER_FREQ);
       return;
     }
   }
   if (!enabled && isLowPower) {
     LOG_DBG("PWR", "Restoring normal CPU frequency");
     if (!setCpuFrequencyMhz(normalFreq)) {
-      LOG_ERR("PWR", "Failed to restore normal CPU frequency");
+      LOG_DBG("PWR", "Failed to set CPU frequency = %d MHz", normalFreq);
       return;
     }
   }

platformio.ini

@@ -27,9 +27,15 @@ build_flags =
 # https://libexpat.github.io/doc/api/latest/#XML_GE
   -DXML_GE=0
   -DXML_CONTEXT_BYTES=1024
-  -std=c++2a
+  -std=gnu++2a
 # Enable UTF-8 long file names in SdFat
   -DUSE_UTF8_LONG_NAMES=1
+# Increase PNG scanline buffer to support up to 800px wide images
+# Default is (320*4+1)*2=2562, we need more for larger images
+  -DPNG_MAX_BUFFERED_PIXELS=6402
+
+build_unflags =
+  -std=gnu++11
 
 ; Board configuration
 board_build.flash_mode = dio
@@ -47,6 +53,7 @@ lib_deps =
   SDCardManager=symlink://open-x4-sdk/libs/hardware/SDCardManager
   bblanchon/ArduinoJson @ 7.4.2
   ricmoo/QRCode @ 0.0.1
+  bitbank2/PNGdec @ ^1.0.0
   links2004/WebSockets @ 2.7.3
 
 [env:default]

scripts/generate_test_epub.py

@@ -0,0 +1,501 @@
+#!/usr/bin/env python3
+"""
+Generate test EPUBs for image rendering verification.
+
+Creates EPUBs with annotated JPEG and PNG images to verify:
+- Grayscale rendering (4 levels)
+- Image scaling
+- Image centering
+- Cache performance
+- Page serialization
+"""
+
+import os
+import zipfile
+from pathlib import Path
+
+try:
+    from PIL import Image, ImageDraw, ImageFont
+except ImportError:
+    print("Please install Pillow: pip install Pillow")
+    exit(1)
+
+OUTPUT_DIR = Path(__file__).parent.parent / "test" / "epubs"
+SCREEN_WIDTH = 480
+SCREEN_HEIGHT = 800
+
+def get_font(size=20):
+    """Get a font, falling back to default if needed."""
+    try:
+        return ImageFont.truetype("/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf", size)
+    except:
+        try:
+            return ImageFont.truetype("/usr/share/fonts/TTF/DejaVuSans.ttf", size)
+        except:
+            return ImageFont.load_default()
+
+def draw_text_centered(draw, y, text, font, fill=0):
+    """Draw centered text at given y position."""
+    bbox = draw.textbbox((0, 0), text, font=font)
+    text_width = bbox[2] - bbox[0]
+    x = (draw.im.size[0] - text_width) // 2
+    draw.text((x, y), text, font=font, fill=fill)
+
+def draw_text_wrapped(draw, x, y, text, font, max_width, fill=0):
+    """Draw text with word wrapping."""
+    words = text.split()
+    lines = []
+    current_line = []
+
+    for word in words:
+        test_line = ' '.join(current_line + [word])
+        bbox = draw.textbbox((0, 0), test_line, font=font)
+        if bbox[2] - bbox[0] <= max_width:
+            current_line.append(word)
+        else:
+            if current_line:
+                lines.append(' '.join(current_line))
+            current_line = [word]
+    if current_line:
+        lines.append(' '.join(current_line))
+
+    line_height = font.size + 4 if hasattr(font, 'size') else 20
+    for i, line in enumerate(lines):
+        draw.text((x, y + i * line_height), line, font=font, fill=fill)
+
+    return len(lines) * line_height
+
+def create_grayscale_test_image(filename, is_png=True):
+    """
+    Create image with 4 grayscale squares to verify 4-level rendering.
+    """
+    width, height = 400, 600
+    img = Image.new('L', (width, height), 255)
+    draw = ImageDraw.Draw(img)
+    font = get_font(16)
+    font_small = get_font(14)
+
+    # Title
+    draw_text_centered(draw, 10, "GRAYSCALE TEST", font, fill=0)
+    draw_text_centered(draw, 35, "Verify 4 distinct gray levels", font_small, fill=64)
+
+    # Draw 4 grayscale squares
+    square_size = 70
+    start_y = 65
+    gap = 10
+
+    levels = [
+        (0, "Level 0: BLACK"),
+        (96, "Level 1: DARK GRAY"),
+        (160, "Level 2: LIGHT GRAY"),
+        (255, "Level 3: WHITE"),
+    ]
+
+    for i, (gray_value, label) in enumerate(levels):
+        y = start_y + i * (square_size + gap + 22)
+        x = (width - square_size) // 2
+
+        # Draw square with border
+        draw.rectangle([x-2, y-2, x + square_size + 2, y + square_size + 2], fill=0)
+        draw.rectangle([x, y, x + square_size, y + square_size], fill=gray_value)
+
+        # Label below square
+        bbox = draw.textbbox((0, 0), label, font=font_small)
+        label_width = bbox[2] - bbox[0]
+        draw.text(((width - label_width) // 2, y + square_size + 5), label, font=font_small, fill=0)
+
+    # Instructions at bottom
+    y = height - 70
+    draw_text_centered(draw, y, "PASS: 4 distinct shades visible", font_small, fill=0)
+    draw_text_centered(draw, y + 20, "FAIL: Only black/white or", font_small, fill=64)
+    draw_text_centered(draw, y + 38, "muddy/indistinct grays", font_small, fill=64)
+
+    if is_png:
+        img.save(filename, 'PNG')
+    else:
+        img.save(filename, 'JPEG', quality=95)
+
+def create_centering_test_image(filename, is_png=True):
+    """
+    Create image with border markers to verify centering.
+    """
+    width, height = 350, 400
+    img = Image.new('L', (width, height), 255)
+    draw = ImageDraw.Draw(img)
+    font = get_font(16)
+    font_small = get_font(14)
+
+    # Draw border
+    draw.rectangle([0, 0, width-1, height-1], outline=0, width=3)
+
+    # Corner markers
+    marker_size = 20
+    for x, y in [(0, 0), (width-marker_size, 0), (0, height-marker_size), (width-marker_size, height-marker_size)]:
+        draw.rectangle([x, y, x+marker_size, y+marker_size], fill=0)
+
+    # Center cross
+    cx, cy = width // 2, height // 2
+    draw.line([cx - 30, cy, cx + 30, cy], fill=0, width=2)
+    draw.line([cx, cy - 30, cx, cy + 30], fill=0, width=2)
+
+    # Title
+    draw_text_centered(draw, 40, "CENTERING TEST", font, fill=0)
+
+    # Instructions
+    y = 80
+    draw_text_centered(draw, y, "Image should be centered", font_small, fill=0)
+    draw_text_centered(draw, y + 20, "horizontally on screen", font_small, fill=0)
+
+    y = 150
+    draw_text_centered(draw, y, "Check:", font_small, fill=0)
+    draw_text_centered(draw, y + 25, "- Equal margins left & right", font_small, fill=64)
+    draw_text_centered(draw, y + 45, "- All 4 corners visible", font_small, fill=64)
+    draw_text_centered(draw, y + 65, "- Border is complete rectangle", font_small, fill=64)
+
+    # Pass/fail
+    y = height - 80
+    draw_text_centered(draw, y, "PASS: Centered, all corners visible", font_small, fill=0)
+    draw_text_centered(draw, y + 20, "FAIL: Off-center or cropped", font_small, fill=64)
+
+    if is_png:
+        img.save(filename, 'PNG')
+    else:
+        img.save(filename, 'JPEG', quality=95)
+
+def create_scaling_test_image(filename, is_png=True):
+    """
+    Create large image to verify scaling works.
+    """
+    width, height = 1200, 1500
+    img = Image.new('L', (width, height), 240)
+    draw = ImageDraw.Draw(img)
+    font = get_font(48)
+    font_medium = get_font(32)
+    font_small = get_font(24)
+
+    # Border
+    draw.rectangle([0, 0, width-1, height-1], outline=0, width=8)
+    draw.rectangle([20, 20, width-21, height-21], outline=128, width=4)
+
+    # Title
+    draw_text_centered(draw, 60, "SCALING TEST", font, fill=0)
+    draw_text_centered(draw, 130, f"Original: {width}x{height} (larger than screen)", font_medium, fill=64)
+
+    # Grid pattern
+    grid_start_y = 220
+    grid_size = 400
+    cell_size = 50
+
+    draw_text_centered(draw, grid_start_y - 40, "Grid pattern (check for artifacts):", font_small, fill=0)
+
+    grid_x = (width - grid_size) // 2
+    for row in range(grid_size // cell_size):
+        for col in range(grid_size // cell_size):
+            x = grid_x + col * cell_size
+            y = grid_start_y + row * cell_size
+            if (row + col) % 2 == 0:
+                draw.rectangle([x, y, x + cell_size, y + cell_size], fill=0)
+            else:
+                draw.rectangle([x, y, x + cell_size, y + cell_size], fill=200)
+
+    # Pass/fail
+    y = height - 100
+    draw_text_centered(draw, y, "PASS: Scaled down, readable, complete", font_small, fill=0)
+    draw_text_centered(draw, y + 30, "FAIL: Cropped, distorted, or unreadable", font_small, fill=64)
+
+    if is_png:
+        img.save(filename, 'PNG')
+    else:
+        img.save(filename, 'JPEG', quality=95)
+
+def create_cache_test_image(filename, page_num, is_png=True):
+    """
+    Create image for cache performance testing.
+    """
+    width, height = 400, 300
+    img = Image.new('L', (width, height), 255)
+    draw = ImageDraw.Draw(img)
+    font = get_font(18)
+    font_small = get_font(14)
+    font_large = get_font(36)
+
+    # Border
+    draw.rectangle([0, 0, width-1, height-1], outline=0, width=2)
+
+    # Page number prominent
+    draw_text_centered(draw, 30, f"CACHE TEST PAGE {page_num}", font, fill=0)
+    draw_text_centered(draw, 80, f"#{page_num}", font_large, fill=0)
+
+    # Instructions
+    y = 140
+    draw_text_centered(draw, y, "Navigate away then return", font_small, fill=64)
+    draw_text_centered(draw, y + 25, "Second load should be faster", font_small, fill=64)
+
+    y = 220
+    draw_text_centered(draw, y, "PASS: Faster reload from cache", font_small, fill=0)
+    draw_text_centered(draw, y + 20, "FAIL: Same slow decode each time", font_small, fill=64)
+
+    if is_png:
+        img.save(filename, 'PNG')
+    else:
+        img.save(filename, 'JPEG', quality=95)
+
+def create_format_test_image(filename, format_name, is_png=True):
+    """
+    Create simple image to verify format support.
+    """
+    width, height = 350, 250
+    img = Image.new('L', (width, height), 255)
+    draw = ImageDraw.Draw(img)
+    font = get_font(20)
+    font_large = get_font(36)
+    font_small = get_font(14)
+
+    # Border
+    draw.rectangle([0, 0, width-1, height-1], outline=0, width=3)
+
+    # Format name
+    draw_text_centered(draw, 30, f"{format_name} FORMAT TEST", font, fill=0)
+    draw_text_centered(draw, 80, format_name, font_large, fill=0)
+
+    # Checkmark area
+    y = 140
+    draw_text_centered(draw, y, "If you can read this,", font_small, fill=64)
+    draw_text_centered(draw, y + 20, f"{format_name} decoding works!", font_small, fill=64)
+
+    y = height - 40
+    draw_text_centered(draw, y, f"PASS: {format_name} image visible", font_small, fill=0)
+
+    if is_png:
+        img.save(filename, 'PNG')
+    else:
+        img.save(filename, 'JPEG', quality=95)
+
+def create_epub(epub_path, title, chapters):
+    """
+    Create an EPUB file with the given chapters.
+
+    chapters: list of (chapter_title, html_content, images)
+              images: list of (image_filename, image_data)
+    """
+    with zipfile.ZipFile(epub_path, 'w', zipfile.ZIP_DEFLATED) as epub:
+        # mimetype (must be first, uncompressed)
+        epub.writestr('mimetype', 'application/epub+zip', compress_type=zipfile.ZIP_STORED)
+
+        # Container
+        container_xml = '''<?xml version="1.0" encoding="UTF-8"?>
+<container version="1.0" xmlns="urn:oasis:names:tc:opendocument:xmlns:container">
+  <rootfiles>
+    <rootfile full-path="OEBPS/content.opf" media-type="application/oebps-package+xml"/>
+  </rootfiles>
+</container>'''
+        epub.writestr('META-INF/container.xml', container_xml)
+
+        # Collect all images and chapters
+        manifest_items = []
+        spine_items = []
+
+        # Add chapters and images
+        for i, (chapter_title, html_content, images) in enumerate(chapters):
+            chapter_id = f'chapter{i+1}'
+            chapter_file = f'chapter{i+1}.xhtml'
+
+            # Add images for this chapter
+            for img_filename, img_data in images:
+                media_type = 'image/png' if img_filename.endswith('.png') else 'image/jpeg'
+                manifest_items.append(f'    <item id="{img_filename.replace(".", "_")}" href="images/{img_filename}" media-type="{media_type}"/>')
+                epub.writestr(f'OEBPS/images/{img_filename}', img_data)
+
+            # Add chapter
+            manifest_items.append(f'    <item id="{chapter_id}" href="{chapter_file}" media-type="application/xhtml+xml"/>')
+            spine_items.append(f'    <itemref idref="{chapter_id}"/>')
+            epub.writestr(f'OEBPS/{chapter_file}', html_content)
+
+        # content.opf
+        content_opf = f'''<?xml version="1.0" encoding="UTF-8"?>
+<package xmlns="http://www.idpf.org/2007/opf" version="3.0" unique-identifier="uid">
+  <metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
+    <dc:identifier id="uid">test-epub-{title.lower().replace(" ", "-")}</dc:identifier>
+    <dc:title>{title}</dc:title>
+    <dc:language>en</dc:language>
+  </metadata>
+  <manifest>
+    <item id="nav" href="nav.xhtml" media-type="application/xhtml+xml" properties="nav"/>
+{chr(10).join(manifest_items)}
+  </manifest>
+  <spine>
+{chr(10).join(spine_items)}
+  </spine>
+</package>'''
+        epub.writestr('OEBPS/content.opf', content_opf)
+
+        # Navigation document
+        nav_items = '\n'.join([f'      <li><a href="chapter{i+1}.xhtml">{chapters[i][0]}</a></li>'
+                               for i in range(len(chapters))])
+        nav_xhtml = f'''<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE html>
+<html xmlns="http://www.w3.org/1999/xhtml" xmlns:epub="http://www.idpf.org/2007/ops">
+<head><title>Navigation</title></head>
+<body>
+  <nav epub:type="toc">
+    <h1>Contents</h1>
+    <ol>
+{nav_items}
+    </ol>
+  </nav>
+</body>
+</html>'''
+        epub.writestr('OEBPS/nav.xhtml', nav_xhtml)
+
+def make_chapter(title, body_content):
+    """Create XHTML chapter content."""
+    return f'''<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE html>
+<html xmlns="http://www.w3.org/1999/xhtml">
+<head><title>{title}</title></head>
+<body>
+<h1>{title}</h1>
+{body_content}
+</body>
+</html>'''
+
+def main():
+    OUTPUT_DIR.mkdir(exist_ok=True)
+
+    import tempfile
+    with tempfile.TemporaryDirectory() as tmpdir:
+        tmpdir = Path(tmpdir)
+
+        print("Generating test images...")
+
+        images = {}
+
+        # JPEG tests
+        create_grayscale_test_image(tmpdir / 'grayscale_test.jpg', is_png=False)
+        create_centering_test_image(tmpdir / 'centering_test.jpg', is_png=False)
+        create_scaling_test_image(tmpdir / 'scaling_test.jpg', is_png=False)
+        create_format_test_image(tmpdir / 'jpeg_format.jpg', 'JPEG', is_png=False)
+        create_cache_test_image(tmpdir / 'cache_test_1.jpg', 1, is_png=False)
+        create_cache_test_image(tmpdir / 'cache_test_2.jpg', 2, is_png=False)
+
+        # PNG tests
+        create_grayscale_test_image(tmpdir / 'grayscale_test.png', is_png=True)
+        create_centering_test_image(tmpdir / 'centering_test.png', is_png=True)
+        create_scaling_test_image(tmpdir / 'scaling_test.png', is_png=True)
+        create_format_test_image(tmpdir / 'png_format.png', 'PNG', is_png=True)
+        create_cache_test_image(tmpdir / 'cache_test_1.png', 1, is_png=True)
+        create_cache_test_image(tmpdir / 'cache_test_2.png', 2, is_png=True)
+
+        # Read all images
+        for img_file in tmpdir.glob('*.*'):
+            images[img_file.name] = img_file.read_bytes()
+
+        print("Creating JPEG test EPUB...")
+        jpeg_chapters = [
+            ("Introduction", make_chapter("JPEG Image Tests", """
+<p>This EPUB tests JPEG image rendering.</p>
+<p>Navigate through chapters to verify each test case.</p>
+"""), []),
+            ("1. JPEG Format", make_chapter("JPEG Format Test", """
+<p>Basic JPEG decoding test.</p>
+<img src="images/jpeg_format.jpg" alt="JPEG format test"/>
+<p>If the image above is visible, JPEG decoding works.</p>
+"""), [('jpeg_format.jpg', images['jpeg_format.jpg'])]),
+            ("2. Grayscale", make_chapter("Grayscale Test", """
+<p>Verify 4 distinct gray levels are visible.</p>
+<img src="images/grayscale_test.jpg" alt="Grayscale test"/>
+"""), [('grayscale_test.jpg', images['grayscale_test.jpg'])]),
+            ("3. Centering", make_chapter("Centering Test", """
+<p>Verify image is centered horizontally.</p>
+<img src="images/centering_test.jpg" alt="Centering test"/>
+"""), [('centering_test.jpg', images['centering_test.jpg'])]),
+            ("4. Scaling", make_chapter("Scaling Test", """
+<p>This image is 1200x1500 pixels - larger than the screen.</p>
+<p>It should be scaled down to fit.</p>
+<img src="images/scaling_test.jpg" alt="Scaling test"/>
+"""), [('scaling_test.jpg', images['scaling_test.jpg'])]),
+            ("5. Cache Test A", make_chapter("Cache Test - Page A", """
+<p>First cache test page. Note the load time.</p>
+<img src="images/cache_test_1.jpg" alt="Cache test 1"/>
+<p>Navigate to next page, then come back.</p>
+"""), [('cache_test_1.jpg', images['cache_test_1.jpg'])]),
+            ("6. Cache Test B", make_chapter("Cache Test - Page B", """
+<p>Second cache test page.</p>
+<img src="images/cache_test_2.jpg" alt="Cache test 2"/>
+<p>Navigate back to Page A - it should load faster from cache.</p>
+"""), [('cache_test_2.jpg', images['cache_test_2.jpg'])]),
+        ]
+
+        create_epub(OUTPUT_DIR / 'test_jpeg_images.epub', 'JPEG Image Tests', jpeg_chapters)
+
+        print("Creating PNG test EPUB...")
+        png_chapters = [
+            ("Introduction", make_chapter("PNG Image Tests", """
+<p>This EPUB tests PNG image rendering.</p>
+<p>Navigate through chapters to verify each test case.</p>
+"""), []),
+            ("1. PNG Format", make_chapter("PNG Format Test", """
+<p>Basic PNG decoding test.</p>
+<img src="images/png_format.png" alt="PNG format test"/>
+<p>If the image above is visible and no crash occurred, PNG decoding works.</p>
+"""), [('png_format.png', images['png_format.png'])]),
+            ("2. Grayscale", make_chapter("Grayscale Test", """
+<p>Verify 4 distinct gray levels are visible.</p>
+<img src="images/grayscale_test.png" alt="Grayscale test"/>
+"""), [('grayscale_test.png', images['grayscale_test.png'])]),
+            ("3. Centering", make_chapter("Centering Test", """
+<p>Verify image is centered horizontally.</p>
+<img src="images/centering_test.png" alt="Centering test"/>
+"""), [('centering_test.png', images['centering_test.png'])]),
+            ("4. Scaling", make_chapter("Scaling Test", """
+<p>This image is 1200x1500 pixels - larger than the screen.</p>
+<p>It should be scaled down to fit.</p>
+<img src="images/scaling_test.png" alt="Scaling test"/>
+"""), [('scaling_test.png', images['scaling_test.png'])]),
+            ("5. Cache Test A", make_chapter("Cache Test - Page A", """
+<p>First cache test page. Note the load time.</p>
+<img src="images/cache_test_1.png" alt="Cache test 1"/>
+<p>Navigate to next page, then come back.</p>
+"""), [('cache_test_1.png', images['cache_test_1.png'])]),
+            ("6. Cache Test B", make_chapter("Cache Test - Page B", """
+<p>Second cache test page.</p>
+<img src="images/cache_test_2.png" alt="Cache test 2"/>
+<p>Navigate back to Page A - it should load faster from cache.</p>
+"""), [('cache_test_2.png', images['cache_test_2.png'])]),
+        ]
+
+        create_epub(OUTPUT_DIR / 'test_png_images.epub', 'PNG Image Tests', png_chapters)
+
+        print("Creating mixed format test EPUB...")
+        mixed_chapters = [
+            ("Introduction", make_chapter("Mixed Image Format Tests", """
+<p>This EPUB contains both JPEG and PNG images.</p>
+<p>Tests format detection and mixed rendering.</p>
+"""), []),
+            ("1. JPEG Image", make_chapter("JPEG in Mixed EPUB", """
+<p>This is a JPEG image:</p>
+<img src="images/jpeg_format.jpg" alt="JPEG"/>
+"""), [('jpeg_format.jpg', images['jpeg_format.jpg'])]),
+            ("2. PNG Image", make_chapter("PNG in Mixed EPUB", """
+<p>This is a PNG image:</p>
+<img src="images/png_format.png" alt="PNG"/>
+"""), [('png_format.png', images['png_format.png'])]),
+            ("3. Both Formats", make_chapter("Both Formats on One Page", """
+<p>JPEG image:</p>
+<img src="images/grayscale_test.jpg" alt="JPEG grayscale"/>
+<p>PNG image:</p>
+<img src="images/grayscale_test.png" alt="PNG grayscale"/>
+<p>Both should render with proper grayscale.</p>
+"""), [('grayscale_test.jpg', images['grayscale_test.jpg']),
+       ('grayscale_test.png', images['grayscale_test.png'])]),
+        ]
+
+        create_epub(OUTPUT_DIR / 'test_mixed_images.epub', 'Mixed Format Tests', mixed_chapters)
+
+        print(f"\nTest EPUBs created in: {OUTPUT_DIR}")
+        print("Files:")
+        for f in OUTPUT_DIR.glob('*.epub'):
+            print(f"  - {f.name}")
+
+if __name__ == '__main__':
+    main()

src/RecentBooksStore.cpp

@@ -38,6 +38,15 @@ void RecentBooksStore::addBook(const std::string& path, const std::string& title
   saveToFile();
 }
 
+void RecentBooksStore::removeBook(const std::string& path) {
+  auto it =
+      std::find_if(recentBooks.begin(), recentBooks.end(), [&](const RecentBook& book) { return book.path == path; });
+  if (it != recentBooks.end()) {
+    recentBooks.erase(it);
+    saveToFile();
+  }
+}
+
 void RecentBooksStore::updateBook(const std::string& path, const std::string& title, const std::string& author,
                                   const std::string& coverBmpPath) {
   auto it =
@@ -88,7 +97,7 @@ RecentBook RecentBooksStore::getDataFromBook(std::string path) const {
   // If epub, try to load the metadata for title/author and cover
   if (StringUtils::checkFileExtension(lastBookFileName, ".epub")) {
     Epub epub(path, "/.crosspoint");
-    epub.load(false);
+    epub.load(false, true);
     return RecentBook{path, epub.getTitle(), epub.getAuthor(), epub.getThumbBmpPath()};
   } else if (StringUtils::checkFileExtension(lastBookFileName, ".xtch") ||
              StringUtils::checkFileExtension(lastBookFileName, ".xtc")) {

src/RecentBooksStore.h

@@ -30,6 +30,9 @@ class RecentBooksStore {
   void updateBook(const std::string& path, const std::string& title, const std::string& author,
                   const std::string& coverBmpPath);
 
+  // Remove a book from the recent list by path
+  void removeBook(const std::string& path);
+
   // Get the list of recent books (most recent first)
   const std::vector<RecentBook>& getBooks() const { return recentBooks; }
 

src/activities/ActivityWithSubactivity.h

@@ -14,4 +14,6 @@ class ActivityWithSubactivity : public Activity {
       : Activity(std::move(name), renderer, mappedInput) {}
   void loop() override;
   void onExit() override;
+  bool preventAutoSleep() override { return subActivity && subActivity->preventAutoSleep(); }
+  bool skipLoopDelay() override { return subActivity && subActivity->skipLoopDelay(); }
 };

src/activities/boot_sleep/SleepActivity.cpp

@@ -642,11 +642,14 @@ void SleepActivity::renderCoverSleepScreen() const {
 
     if (!lastEpub.generateCoverBmp(cropped)) {
       LOG_DBG("SLP", "EPUB cover generation failed, trying placeholder");
-      PlaceholderCoverGenerator::generate(lastEpub.getCoverBmpPath(cropped), lastEpub.getTitle(),
-                                         lastEpub.getAuthor(), 480, 800);
+      if (!PlaceholderCoverGenerator::generate(lastEpub.getCoverBmpPath(cropped), lastEpub.getTitle(),
+                                               lastEpub.getAuthor(), 480, 800)) {
+        LOG_DBG("SLP", "Placeholder generation failed, creating X-pattern marker");
+        lastEpub.generateInvalidFormatCoverBmp(cropped);
+      }
     }
 
-    if (!Storage.exists(lastEpub.getCoverBmpPath(cropped).c_str())) {
+    if (!Epub::isValidThumbnailBmp(lastEpub.getCoverBmpPath(cropped))) {
       LOG_ERR("SLP", "Failed to generate cover bmp");
       return (this->*renderNoCoverSleepScreen)();
     }

src/activities/home/HomeActivity.cpp

@@ -65,7 +65,7 @@ void HomeActivity::loadRecentCovers(int coverHeight) {
   for (RecentBook& book : recentBooks) {
     if (!book.coverBmpPath.empty()) {
       std::string coverPath = UITheme::getCoverThumbPath(book.coverBmpPath, coverHeight);
-      if (!Storage.exists(coverPath.c_str())) {
+      if (!Epub::isValidThumbnailBmp(coverPath)) {
         if (!showingLoading) {
           showingLoading = true;
           popupRect = GUI.drawPopup(renderer, "Loading...");
@@ -74,21 +74,46 @@ void HomeActivity::loadRecentCovers(int coverHeight) {
 
         bool success = false;
 
-        // Try format-specific thumbnail generation first
+        // Try format-specific thumbnail generation first (Real Cover)
         if (StringUtils::checkFileExtension(book.path, ".epub")) {
           Epub epub(book.path, "/.crosspoint");
-          epub.load(false, true);
+          // Try fast cache-only load first; only build cache if missing
+          if (!epub.load(false, true)) {
+            // Cache missing — build it (may take longer)
+            epub.load(true, true);
+          }
           success = epub.generateThumbBmp(coverHeight);
+          if (success) {
+            const std::string thumbPath = epub.getThumbBmpPath(coverHeight);
+            RECENT_BOOKS.updateBook(book.path, book.title, book.author, thumbPath);
+            book.coverBmpPath = thumbPath;
+          } else {
+            // Fallback: generate a placeholder thumbnail with title/author
+            const int thumbWidth = static_cast<int>(coverHeight * 0.6);
+            success = PlaceholderCoverGenerator::generate(coverPath, book.title, book.author, thumbWidth, coverHeight);
+            if (!success) {
+              // Last resort: X-pattern marker to prevent repeated generation attempts
+              epub.generateInvalidFormatThumbBmp(coverHeight);
+            }
+          }
         } else if (StringUtils::checkFileExtension(book.path, ".xtch") ||
                    StringUtils::checkFileExtension(book.path, ".xtc")) {
           Xtc xtc(book.path, "/.crosspoint");
           if (xtc.load()) {
             success = xtc.generateThumbBmp(coverHeight);
+            if (success) {
+              const std::string thumbPath = xtc.getThumbBmpPath(coverHeight);
+              RECENT_BOOKS.updateBook(book.path, book.title, book.author, thumbPath);
+              book.coverBmpPath = thumbPath;
+            }
           }
-        }
-
-        // Fallback: generate a placeholder thumbnail with title/author
-        if (!success && !Storage.exists(coverPath.c_str())) {
+          if (!success) {
+            // Fallback: generate a placeholder thumbnail with title/author
+            const int thumbWidth = static_cast<int>(coverHeight * 0.6);
+            PlaceholderCoverGenerator::generate(coverPath, book.title, book.author, thumbWidth, coverHeight);
+          }
+        } else {
+          // Unknown format: generate a placeholder thumbnail
           const int thumbWidth = static_cast<int>(coverHeight * 0.6);
           PlaceholderCoverGenerator::generate(coverPath, book.title, book.author, thumbWidth, coverHeight);
         }

src/activities/reader/EpubReaderActivity.cpp

@@ -22,6 +22,11 @@
 #include "util/BookmarkStore.h"
 #include "util/Dictionary.h"
 
+// Image refresh optimization strategy:
+// 0 = Use double FAST_REFRESH technique (default, feels snappier)
+// 1 = Use displayWindow() for partial refresh (experimental)
+#define USE_IMAGE_DOUBLE_FAST_REFRESH 0
+
 namespace {
 // pagesPerRefresh now comes from SETTINGS.getRefreshFrequency()
 constexpr unsigned long skipChapterMs = 700;
@@ -126,32 +131,41 @@ void EpubReaderActivity::onEnter() {
         GUI.fillPopupProgress(renderer, popupRect, completedSteps * 100 / totalSteps);
       };
 
-      if (!Storage.exists(epub->getCoverBmpPath(false).c_str())) {
+      if (!Epub::isValidThumbnailBmp(epub->getCoverBmpPath(false))) {
         epub->generateCoverBmp(false);
         // Fallback: generate placeholder if real cover extraction failed
-        if (!Storage.exists(epub->getCoverBmpPath(false).c_str())) {
-          PlaceholderCoverGenerator::generate(epub->getCoverBmpPath(false), epub->getTitle(), epub->getAuthor(), 480,
-                                             800);
+        if (!Epub::isValidThumbnailBmp(epub->getCoverBmpPath(false))) {
+          if (!PlaceholderCoverGenerator::generate(epub->getCoverBmpPath(false), epub->getTitle(), epub->getAuthor(),
+                                                   480, 800)) {
+            // Last resort: X-pattern marker
+            epub->generateInvalidFormatCoverBmp(false);
+          }
         }
         updateProgress();
       }
-      if (!Storage.exists(epub->getCoverBmpPath(true).c_str())) {
+      if (!Epub::isValidThumbnailBmp(epub->getCoverBmpPath(true))) {
         epub->generateCoverBmp(true);
-        if (!Storage.exists(epub->getCoverBmpPath(true).c_str())) {
-          PlaceholderCoverGenerator::generate(epub->getCoverBmpPath(true), epub->getTitle(), epub->getAuthor(), 480,
-                                             800);
+        if (!Epub::isValidThumbnailBmp(epub->getCoverBmpPath(true))) {
+          if (!PlaceholderCoverGenerator::generate(epub->getCoverBmpPath(true), epub->getTitle(), epub->getAuthor(),
+                                                   480, 800)) {
+            // Last resort: X-pattern marker
+            epub->generateInvalidFormatCoverBmp(true);
+          }
         }
         updateProgress();
       }
       for (int i = 0; i < PRERENDER_THUMB_HEIGHTS_COUNT; i++) {
-        if (!Storage.exists(epub->getThumbBmpPath(PRERENDER_THUMB_HEIGHTS[i]).c_str())) {
+        if (!Epub::isValidThumbnailBmp(epub->getThumbBmpPath(PRERENDER_THUMB_HEIGHTS[i]))) {
           epub->generateThumbBmp(PRERENDER_THUMB_HEIGHTS[i]);
           // Fallback: generate placeholder thumbnail
-          if (!Storage.exists(epub->getThumbBmpPath(PRERENDER_THUMB_HEIGHTS[i]).c_str())) {
+          if (!Epub::isValidThumbnailBmp(epub->getThumbBmpPath(PRERENDER_THUMB_HEIGHTS[i]))) {
             const int thumbHeight = PRERENDER_THUMB_HEIGHTS[i];
             const int thumbWidth = static_cast<int>(thumbHeight * 0.6);
-            PlaceholderCoverGenerator::generate(epub->getThumbBmpPath(thumbHeight), epub->getTitle(),
-                                               epub->getAuthor(), thumbWidth, thumbHeight);
+            if (!PlaceholderCoverGenerator::generate(epub->getThumbBmpPath(thumbHeight), epub->getTitle(),
+                                                     epub->getAuthor(), thumbWidth, thumbHeight)) {
+              // Last resort: X-pattern marker
+              epub->generateInvalidFormatThumbBmp(thumbHeight);
+            }
           }
           updateProgress();
         }
@@ -740,6 +754,9 @@ void EpubReaderActivity::onReaderMenuConfirm(EpubReaderMenuActivity::MenuAction
         epub->setupCacheDir();
 
         saveProgress(backupSpine, backupPage, backupPageCount);
+
+        // 5. Remove from recent books so the home screen doesn't show a stale/placeholder cover
+        RECENT_BOOKS.removeBook(epub->getPath());
       }
       xSemaphoreGive(renderingMutex);
       // Defer go home to avoid race condition with display task
@@ -861,6 +878,8 @@ void EpubReaderActivity::renderScreen() {
   }
 
   if (!section) {
+    loadingSection = true;
+
     const auto filepath = epub->getSpineItem(currentSpineIndex).href;
     LOG_DBG("ERS", "Loading file: %s, index: %d", filepath.c_str(), currentSpineIndex);
     section = std::unique_ptr<Section>(new Section(epub, currentSpineIndex, renderer));
@@ -880,6 +899,7 @@ void EpubReaderActivity::renderScreen() {
                                       viewportHeight, SETTINGS.hyphenationEnabled, SETTINGS.embeddedStyle, popupFn)) {
         LOG_ERR("ERS", "Failed to persist page data to SD");
         section.reset();
+        loadingSection = false;
         return;
       }
     } else {
@@ -912,6 +932,8 @@ void EpubReaderActivity::renderScreen() {
       section->currentPage = newPage;
       pendingPercentJump = false;
     }
+
+    loadingSection = false;
   }
 
   renderer.clearScreen();
@@ -967,6 +989,14 @@ void EpubReaderActivity::saveProgress(int spineIndex, int currentPage, int pageC
 void EpubReaderActivity::renderContents(std::unique_ptr<Page> page, const int orientedMarginTop,
                                         const int orientedMarginRight, const int orientedMarginBottom,
                                         const int orientedMarginLeft) {
+  // Determine if this page needs special image handling
+  bool pageHasImages = page->hasImages();
+  bool useAntiAliasing = SETTINGS.textAntiAliasing;
+
+  // Force half refresh for pages with images when anti-aliasing is on,
+  // as grayscale tones require half refresh to display correctly
+  bool forceFullRefresh = pageHasImages && useAntiAliasing;
+
   page->render(renderer, SETTINGS.getReaderFontId(), orientedMarginLeft, orientedMarginTop);
 
   // Draw bookmark ribbon indicator in top-right corner if current page is bookmarked
@@ -985,10 +1015,42 @@ void EpubReaderActivity::renderContents(std::unique_ptr<Page> page, const int or
   }
 
   renderStatusBar(orientedMarginRight, orientedMarginBottom, orientedMarginLeft);
+
+  // Check if half-refresh is needed (either entering Reader or pages counter reached)
   if (pagesUntilFullRefresh <= 1) {
     renderer.displayBuffer(HalDisplay::HALF_REFRESH);
     pagesUntilFullRefresh = SETTINGS.getRefreshFrequency();
+  } else if (forceFullRefresh) {
+    // OPTIMIZATION: For image pages with anti-aliasing, use fast double-refresh technique
+    // to reduce perceived lag. Only when pagesUntilFullRefresh > 1 (screen already clean).
+    int imgX, imgY, imgW, imgH;
+    if (page->getImageBoundingBox(imgX, imgY, imgW, imgH)) {
+      int screenX = imgX + orientedMarginLeft;
+      int screenY = imgY + orientedMarginTop;
+      LOG_DBG("ERS", "Image page: fast double-refresh (page bbox: %d,%d %dx%d, screen: %d,%d %dx%d)",
+              imgX, imgY, imgW, imgH, screenX, screenY, imgW, imgH);
+
+#if USE_IMAGE_DOUBLE_FAST_REFRESH == 0
+      // Method A: Fill blank area + two FAST_REFRESH operations
+      renderer.fillRect(screenX, screenY, imgW, imgH, false);
+      renderer.displayBuffer(HalDisplay::FAST_REFRESH);
+      page->render(renderer, SETTINGS.getReaderFontId(), orientedMarginLeft, orientedMarginTop);
+      renderStatusBar(orientedMarginRight, orientedMarginBottom, orientedMarginLeft);
+      renderer.displayBuffer(HalDisplay::FAST_REFRESH);
+#else
+      // Method B (experimental): Use displayWindow() for partial refresh
+      renderer.displayBuffer(HalDisplay::FAST_REFRESH);
+      page->render(renderer, SETTINGS.getReaderFontId(), orientedMarginLeft, orientedMarginTop);
+      renderStatusBar(orientedMarginRight, orientedMarginBottom, orientedMarginLeft);
+      renderer.displayWindow(screenX, screenY, imgW, imgH, HalDisplay::FAST_REFRESH);
+#endif
+    } else {
+      LOG_DBG("ERS", "Image page but no bbox, using standard half refresh");
+      renderer.displayBuffer(HalDisplay::HALF_REFRESH);
+    }
+    pagesUntilFullRefresh--;
   } else {
+    // Normal page without images, or images without anti-aliasing
     renderer.displayBuffer();
     pagesUntilFullRefresh--;
   }

src/activities/reader/EpubReaderActivity.h

@@ -29,6 +29,7 @@ class EpubReaderActivity final : public ActivityWithSubactivity {
   bool pendingSubactivityExit = false;  // Defer subactivity exit to avoid use-after-free
   bool pendingGoHome = false;           // Defer go home to avoid race condition with display task
   bool skipNextButtonCheck = false;     // Skip button processing for one frame after subactivity exit
+  volatile bool loadingSection = false;  // True during the entire !section block (read from main loop)
   const std::function<void()> onGoBack;
   const std::function<void()> onGoHome;
 
@@ -55,4 +56,10 @@ class EpubReaderActivity final : public ActivityWithSubactivity {
   void onEnter() override;
   void onExit() override;
   void loop() override;
+  // Defer low-power mode and auto-sleep while a section is loading/building.
+  // !section covers the period before the Section object is created (including
+  // cover prerendering in onEnter). loadingSection covers the full !section block
+  // in renderScreen (including createSectionFile), during which section is non-null
+  // but the section file is still being built.
+  bool preventAutoSleep() override { return !section || loadingSection; }
 };

src/activities/reader/ReaderActivity.cpp

@@ -2,6 +2,7 @@
 
 #include <HalStorage.h>
 
+#include "CrossPointSettings.h"
 #include "Epub.h"
 #include "EpubReaderActivity.h"
 #include "Txt.h"
@@ -35,7 +36,7 @@ std::unique_ptr<Epub> ReaderActivity::loadEpub(const std::string& path) {
   }
 
   auto epub = std::unique_ptr<Epub>(new Epub(path, "/.crosspoint"));
-  if (epub->load()) {
+  if (epub->load(true, SETTINGS.embeddedStyle == 0)) {
     return epub;
   }
 

src/activities/reader/TxtReaderActivity.h

@@ -57,4 +57,7 @@ class TxtReaderActivity final : public ActivityWithSubactivity {
   void onEnter() override;
   void onExit() override;
   void loop() override;
+  // Defer low-power mode and auto-sleep while the reader is initializing
+  // (cover prerendering, page index building on first open).
+  bool preventAutoSleep() override { return !initialized; }
 };

src/components/themes/lyra/LyraTheme.cpp

@@ -274,11 +274,10 @@ void LyraTheme::drawRecentBookCover(GfxRenderer& renderer, Rect rect, const std:
       for (int i = 0; i < std::min(static_cast<int>(recentBooks.size()), LyraMetrics::values.homeRecentBooksCount);
            i++) {
         std::string coverPath = recentBooks[i].coverBmpPath;
-        bool hasCover = true;
         int tileX = LyraMetrics::values.contentSidePadding + tileWidth * i;
-        if (coverPath.empty()) {
-          hasCover = false;
-        } else {
+        renderer.drawRect(tileX + hPaddingInSelection, tileY + hPaddingInSelection,
+                          tileWidth - 2 * hPaddingInSelection, LyraMetrics::values.homeCoverHeight);
+        if (!coverPath.empty()) {
           const std::string coverBmpPath = UITheme::getCoverThumbPath(coverPath, LyraMetrics::values.homeCoverHeight);
 
           // First time: load cover from SD and render
@@ -292,20 +291,12 @@ void LyraTheme::drawRecentBookCover(GfxRenderer& renderer, Rect rect, const std:
               const float tileRatio = static_cast<float>(tileWidth - 2 * hPaddingInSelection) /
                                       static_cast<float>(LyraMetrics::values.homeCoverHeight);
               float cropX = 1.0f - (tileRatio / ratio);
-
               renderer.drawBitmap(bitmap, tileX + hPaddingInSelection, tileY + hPaddingInSelection,
                                   tileWidth - 2 * hPaddingInSelection, LyraMetrics::values.homeCoverHeight, cropX);
-            } else {
-              hasCover = false;
             }
             file.close();
           }
         }
-
-        if (!hasCover) {
-          renderer.drawRect(tileX + hPaddingInSelection, tileY + hPaddingInSelection,
-                            tileWidth - 2 * hPaddingInSelection, LyraMetrics::values.homeCoverHeight);
-        }
       }
 
       coverBufferStored = storeCoverBuffer();

src/main.cpp

@@ -440,6 +440,13 @@ void loop() {
     }
   }
 
+  // Re-check preventAutoSleep: the activity may have changed during loop() above
+  // (e.g., HomeActivity transitioned to EpubReaderActivity with pending section work).
+  if (currentActivity && currentActivity->preventAutoSleep()) {
+    lastActivityTime = millis();
+    powerManager.setPowerSaving(false);
+  }
+
   // Add delay at the end of the loop to prevent tight spinning
   // When an activity requests skip loop delay (e.g., webserver running), use yield() for faster response
   // Otherwise, use longer delay to save power