code: public static ImageFormat getImageFormat_WrapIOException(final InputStream is) {
      try {
        return getImageFormat(is);
      } catch (IOException ioe) {
        throw Throwables.propagate(ioe);
      }
    }
docs: /*
  A variant of getImageFormat that wraps IOException with RuntimeException.
  This relieves clients of implementing dummy rethrow try-catch block.