[Gimp-user] matting or anti-aliasing of shapes

[bktheman34 <forums gimpusers com>]

Yes it can be done in GIMP.

Open your image in GIMP. Choose a new background colour which is as close to the
background your image is going to be displayed over. In GIMP click Filters > Web
> Semi flatten. Repeat for each layer of your animation. Now save your GIF. Now
see how it looks when displayed over the background.

-- 
bktheman34 (via www.gimpusers.com/forums)