python image batch

#!/usr/bin/python
import os
import re
from scipy import ndimage, misc

images = []
for root, dirnames, filenames in os.walk("."):
    for filename in filenames:
        if re.search("\.(jpg|jpeg|png)$", filename):
            filepath = os.path.join(root, filename)
            image = ndimage.imread(filepath, mode="L")
            image_resized = misc.imresize(image, (256, 256))
            misc.imsave(filepath, image_resized)