Command line script that takes a path to an image, grayscales image, and then saves the picture in the directory the original image was found in.

gray.py

from  PIL import Image
import os, shutil

print "Please enter location of image"

input = raw_input('> ')

path = os.path.abspath(input)

img = Image.open(path)
size = img.size
new_img = Image.new("L", size)
img.show()

for x in range(0, size[0]):
	for y in range(0, size[1]):
		loc = (x, y)
		pixel = img.getpixel(loc)
		val = (pixel[0] + pixel[1] + pixel[2]) / 3
		new_img.putpixel(loc, val)

filename = "grey_" + os.path.basename(path)
save_to = os.path.dirname(path)
stored = os.getcwd() + '\\' + filename

new_img.show()
new_img.save(filename)

shutil.move(stored, save_to)