code: def do_heavy_work(self, block):
          
          src_file_path = block.latest_file_info.path
          img_path = src_file_path + self.get_extension()
          self.log.debug("Converting file '%s' to image '%s'", src_file_path, img_path)
          from_file_to_image(src_file_path, img_path)
          block.image_converted_file_info = FileInfo(img_path)
          block.latest_file_info = block.image_converted_file_info
          return block
docs: Note: Expects Compressor Block like objects