import Image
import struct

png = Image.open("image.png")
data = png.tobytes()

for b in range(0, len(data), 8):
    bits = struct.unpack('BBBBBBBB', data[b:b+8])
    val = sum(map(lambda (x,y): x*y, zip(bits, [128,64,32,16,8,4,2,1])))
    print('{0} - {1}'.format(bits, chr(val)))

#print repr(data)