def file(self):
        """ Method returns formated photo path - derived from format.id and source Photo filename """
        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])
Method returns formated photo path - derived from format.id and source Photo filename