# -*- coding: cp936 -*- 

import PIL
from PIL import Image,ImageGrab
import os 

im = ImageGrab.grab() 
# or call im.show() to view the image directly 
im.save("c:/screenshot.png")#保存图片 
#os.execvp( "mspaint",('mspaint','c:/screenshot.png'))#调用画图程序打开截屏图片
im1=Image.open("c:/screenshot.png")
print im1.size

rec=(400,400,800,800])
region=im1.crop(rec)
region.show()
region.save("c:/123.bmp")