[Image-SIG] image.transform() data outside image boundaries

[Christopher Schmidt]

When using image.transform, (EXTENT mode) it is possible to select an area 
which contains pixels outside the image:

  out = im.transform((0,100), Image.EXTENT, (-50, -50, 50, 50))

Is there a way to make these pixels transparent, or set their color in
some way?

I'm loading from a GIF, and saving to a PNG. Either of these can change,
if it will help.

Regards,
-- 
Christopher Schmidt
MetaCarta