code: def file(self):
          
          if photos_settings.FORMATED_PHOTO_FILENAME is not None:
              return photos_settings.FORMATED_PHOTO_FILENAME(self)
          source_file = path.split(self.photo.image.name)
          return path.join(source_file[0], str(self.format.id) + '-' + source_file[1])
docs: Method returns formated photo path - derived from format.id and source Photo filename