// I hereby release this code under the CC0 1.0 Universal license. https://creativecommons.org/publicdomain/zero/1.0/

def avhash(im):
    im = im.resize((8, 8), Image.ANTIALIAS).convert('L')
    avg = reduce(lambda x, y: x + y, im.getdata()) / 64.
    return reduce(lambda x, (y, z): x | (z << y),
                  enumerate(map(lambda i: 0 if i < avg else 1, im.getdata())),
                  0)