code: protected void onInvalidArtwork(@NonNull Artwork artwork) {
          Uri artworkUri = ContentUris.withAppendedId(contentUri, artwork.getId());
          delete(artworkUri, null, null);
      }
docs: Called when Muzei failed to load the given artwork, usually due to an incompatibility
  in supported image format. The default behavior is to delete the artwork.
  <p>
  If you only support a single artwork, you should use this callback as an opportunity
  to provide an alternate version of the artwork or a backup image to avoid repeatedly
  loading the same artwork, just to mark it as invalid and be left with no valid artwork.
  
  @param artwork Artwork that Muzei has failed to load