docs: def get_series_images(self, series_id, image_type=None, resolution=None, sub_key=None):
          """
          Retrieves the url to images (posters, fanart) for the series, seasons and episodes of a series given its
          TheTVDB id and filtered by additional parameters.
  
          :param series_id: The TheTVDB id of the series.
          :param image_type: The optional type of image: posters, fanart, thumbnail, etc.
          :param resolution: The optional resolution: i.e. 1280x1024
          :param sub_key: The optional subkey: graphical, text.
          :return: a python dictionary with either the result of the search or an error from TheTVDB.
          """
  
          arguments = locals()
          optional_parameters = {'image_type': 'keyType', 'resolution': 'resolution', 'sub_key': 'subKey'}
  
          query_string = utils.query_param_string_from_option_args(optional_parameters, arguments)
  
          if len(query_string):
  
              raw_response = requests_util.run_request('get', self.API_BASE_URL + '/series/%d/images/query?%s' %
                                                       (series_id, query_string), headers=self.__get_header_with_auth())
              return self.parse_raw_response(raw_response)
          else:
              return self.__get_series_images(series_id)