code: def current_arg_images(self) -> List[str]:
          
          if self._current_arg_images is None:
              self._current_arg_images = [
                  s.data['url'] for s in Message(self.current_arg)
                  if s.type == 'image' and 'url' in s.data
              ]
          return self._current_arg_images
docs: Images (as list of urls) in the current argument.