srecord noeq PicturesByMD5(File dir) {
  settable S extension = ".jpeg";
  
  File imageFile(S md5) {
    ret newFile(dir, assertMD5(md5) + extension);
  }
  
  bool has(S md5) { ret isFile(imageFile(md5)); }
  
  BufferedImage get(S md5) {
    ret decodeImage(imageFile(md5));
  }
  
  swappable BufferedImage decodeImage(File f) {
    ret loadImage2(f);
  }
  
  bool put(S md5, byte[] imageData) {
    if (has(md5)) false;
    saveBinaryFile(imageFile(md5), imageData);
    true;
  }
  
  // -actually scans the directory
  // -only sees files with the correct extension
  int freshImageCount() {
    ret l(listFilesWithExtension(dir, extension));
  }
}