[Gimp-user] transparent backgrounds?

[Nels H.]

I would like to fill an image with faces copied from other photos.  I am
stumped with how to make the background of the copied faces transparent, so I
don't have a bunch of little squares and ellipses. I am sure Gimp is capable
of selecting the backgrounds of my thumbnails and rendering them transparent. 


Would somebody please help me understand how to ask it to do that?

-- 
Nels H. (via www.gimpusers.com)