This is an application of the Python Image Library (PIL) and shows you how simple it is to do pixel math on an image.

# do pixel math on an image using the PIL image library
# free from:
# Python23 tested      vegaseat     22jan2005

import Image

# open an image file (.jpg or.png) you have in the working folder
im1 ="Audi.jpg")

# multiply each pixel by 0.9 (makes the image darker)
# works best with .jpg and .png files, darker < 1.0 < lighter
# (.bmp and .gif files give goofy results)
# note that lambda is akin to a one-line function
im2 = im1.point(lambda p: p * 0.9)

# brings up the modified image in a viewer, simply saves the image as
# a bitmap to a temporary file and calls viewer associated with .bmp
# make certain you have associated an image viewer with this file type

# save modified image to working folder as Audi2.jpg"Audi2.jpg")

At this point PIL is only available for Python v2.3, sorry! I hope this will change soon.