transient sclass ImagePreviewCache {
  // max bytes in memory
  settable long maxSize;
  
  // estimated bytes in memory
  gettable long totalSize;
  
  new TheMap map;
  
  class TheMap extends LinkedHashMap<File, BufferedImage> {
    protected bool removeEldestEntry(Map.Entry eldest) {
      if (totalSize > maxSize) {
        totalSize -= guessImageSize(eldest.getValue());
        true;
      }
      false;
    }
  }
  
  int guessImageSize(BufferedImage image) {
    ret guessImageSizeInMemory(image);
  }
  
  BufferedImage makeThumbnail(File file) {
    ret loadImage2();
  }
}