public static String getThumbUri(ICoverArt cover) {
   if (cover.getThumbnail() != null) {
     return cover.getThumbnail();
   }
   final String hex = Crc32.formatAsHexLowerCase(cover.getCrc());
   return THUMB_PREFIX + hex.charAt(0) + "/" + hex + ".tbn";
 }
 public static String getFallbackThumbUri(ICoverArt cover) {
   final int crc = cover.getFallbackCrc();
   if (crc != 0) {
     final String hex = Crc32.formatAsHexLowerCase(crc);
     return THUMB_PREFIX + hex.charAt(0) + "/" + hex + ".tbn";
   } else {
     return null;
   }
 }