[Tutor] saving Tkinter canvas as jpg

[Benjamin Fishbein]

Hello.
I'm writing a program to draw pictures. I'm using Python 2.7.3 on Mac OSx. I'm trying to find a good way to save the canvas as a jpg (or other pic formats). The advice I've found on stackoverflow is ImageGrab from PIL, but apparently that doesn't work for macs. I get the "no module named _grabscreen" ImportError.
Can you recommend a good module for saving the canvas into a picture file?
Thank you,
Ben