def get_tile_image_by_gid(self, gid):
        """ Return the tile image for this location

        :param gid: GID of image
        :rtype: surface if found, otherwise ValueError
        """
        try:
            assert (int(gid) >= 0)
            return self.images[gid]
        except TypeError:
            msg = "GIDs must be expressed as a number.  Got: {0}"
            logger.debug(msg.format(gid))
            raise TypeError
        except (AssertionError, IndexError):
            msg = "Coords: ({0},{1}) in layer {2} has invalid GID: {3}"
            logger.debug(msg.format(gid))
            raise ValueError
Return the tile image for this location

        :param gid: GID of image
        :rtype: surface if found, otherwise ValueError