code: def keep_file(self, task, response, min_size=None, max_size=None):
          
          try:
              img = Image.open(BytesIO(response.content))
          except (IOError, OSError):
              return False
          task['img_size'] = img.size
          if min_size and not self._size_gt(img.size, min_size):
              return False
          if max_size and not self._size_lt(img.size, max_size):
              return False
          return True
docs: Decide whether to keep the image
  
          Compare image size with ``min_size`` and ``max_size`` to decide.
  
          Args:
              response (Response): response of requests.
              min_size (tuple or None): minimum size of required images.
              max_size (tuple or None): maximum size of required images.
          Returns:
              bool: whether to keep the image.