iOS Icon Resize Simple Script (Python)

#!/usr/bin/python

import sys
import os.path
from PIL import Image #windows
# import Image #MacOS
import string

###USAGE: python ios_icon_resize.py

### Script by Firecracker Software
### http://www.firecrackersw.com
### Use freely; no attribution required.

### This script relies on PIL, the Python Image Library.
### It will not work with the newer "Pillow" image library.

### Place this script in a directory containing your iTunesArtwork@2x
### asset (1024x1024 px) and run from command line.

EXPORT_QUALITY=100

def main():

    #Import the image into an image object.
    im = Image.open("iTunesArtwork@2x.png")
    width = im.size[0]
    height = im.size[1]

    #Resize for all known icon sizes.
    resize(im, "Icon-20", 20, 20)
    resize(im, "Icon-20@2x", 40, 40)
    resize(im, "Icon-20@3x", 60, 60)

    resize(im, "Icon-29", 29, 29)
    resize(im, "Icon-29@2x", 58, 58)
    resize(im, "Icon-29@3x", 87, 87)

    resize(im, "Icon-40", 40, 40)
    resize(im, "Icon-40@2x", 80, 80)
    resize(im, "Icon-40@3x", 120, 120)

    resize(im, "Icon-57", 57, 57)
    resize(im, "Icon-57@2x", 114, 114)

    resize(im, "Icon-60@2x", 120, 120)
    resize(im, "Icon-60@3x", 180, 180)

    resize(im, "Icon-50", 50, 50)
    resize(im, "Icon-50@2x", 100, 100)

    resize(im, "Icon-72", 72, 72)
    resize(im, "Icon-72@2x", 144, 144)

    resize(im, "Icon-76", 76, 76)
    resize(im, "Icon-76@2x", 152, 152)

    resize(im, "Icon-83.5@2x", 167, 167)

    resize(im, "iTunesArtwork", 512, 512)
    #With iTunesArtwork@2x taken as granted.

def resize(im, name, width, height):
    #Resize the image object to the target size.
    im = im.resize((height, height), Image.ANTIALIAS)

    #Perform cropping pass.  Really only useful for iOS 6 and below.
    left = (height - width)/2       #Crops from center of icon.
    top = 0
    right = (height + width)/2
    bottom = height
    finalcrop = im.crop((left, top, right, bottom))

    #Save the final result.
    finalcrop.save(str(name) + ".png", quality=EXPORT_QUALITY)

if __name__ == "__main__":
    main()