PIL Expand Canvas

[Daniel Bowett]

I'm new to the PIL module but think it would be useful for dealing with 
all the product images for the sites I work on. I can see how to do most 
things I need apart from expanding the canvas.

By that I mean if I have an image which is 200 pixels high and 180 
pixels wide - I will want to pad it left and right by 10 pixels with 
white space to make it a 200x200 square.

Is this possible?