def render_transparent_chit():
    """ Render a transparent chit for external, sized images """

    if request.if_none_match.contains('chit') or request.if_modified_since:
        return 'Not modified', 304

    out_bytes = base64.b64decode(
        "R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7")
    return out_bytes, {'Content-Type': 'image/gif', 'ETag': 'chit',
                       'Last-Modified': 'Tue, 31 Jul 1990 08:00:00 -0000'}
Render a transparent chit for external, sized images