swap each color band of image

bandswap.py

import Image

def bandswap(pr,pg,pb):
    im = Image.open('Lenna.png')
    b = im.split()
    im = Image.merge('RGB', (b[pr], b[pg], b[pb]))
    im.save('Lenna_%d%d%d.png'%(pr,pg,pb));

if __name__ == '__main__':
    bandswap(0,1,2)
    bandswap(1,2,0)
    bandswap(2,0,1)
    bandswap(2,1,0)
    bandswap(0,2,1)
    bandswap(1,0,2)