create watermarks with Python PIL

watermark.py

import Image, ImageEnhance, os
from os.path import join

def test():
    batch("./src", "./dst", "./logo/watermark.png")

def batch(infolder, outfolder, watermark):
    mark = Image.open(watermark)
    for root, dirs, files in os.walk(infolder):
        for name in files:        
            try:
                im = Image.open(join(root, name))
                if im.mode != 'RGBA':
                    im = im.convert('RGBA')
                layer = Image.new('RGBA', im.size, (0,0,0,0))
                position = (im.size[0]/2-mark.size[0]/2, im.size[1]/2-mark.size[1]/2)
                layer.paste(mark, position)
                Image.composite(layer, im, layer).save( join(outfolder, name))
            except Exception, (msg):
                print msg

if __name__ == '__main__':
    test()