Resize a set of images by a given percentage

image_resize.py

#!/usr/bin/env python
#
# Resize a set of images by a given percentage.

import sys, os
from PIL import Image


if __name__ == '__main__':
    if len(sys.argv) > 2:
        percentage = int(sys.argv[1]) / float(100)
        print 'Resizing each image by %s%%' % (percentage * 100)
        imgs = sys.argv[2:]
        for fname in imgs:
            img = Image.open(fname)
            w, h = img.size
            img = img.resize(
                (int(w * percentage), int(h * percentage)),
                Image.BILINEAR
            )   
            img.save("resize_%s" % fname)
    else:
        print '%s <percentage> [file ...]' % os.path.basename(sys.argv[0])