Image Corrupter

#! /usr/bin/env python

import os, random

# Put an image called "Image.jpeg" in the fame directory as the script
# Run the script
# You will have a folder called "Images", which will have 26 images, lettered a-z, all with different results

lettersList = map(chr, range(97, 123))

workDir = os.path.dirname(os.path.realpath(__file__))
image = open("%s/Image.jpeg" % workDir)
filedataBackup = image.read()
filedata = filedataBackup

os.mkdir("%s/Images" % workDir)

for currentLetter in lettersList:
    randLetter = random.choice(lettersList)
    if currentLetter == randLetter:
        randLetter = "."
    filedata = filedata.replace(currentLetter, randLetter)
    target = open("%s/Images/%s.jpeg" % (workDir, currentLetter), 'w+')
    target.write(filedata)
    filedata = filedataBackup