Do you magnetic lasso the images then copy and paste them into backgrounds?
Since I have GIMP and am not in possession of such a tool (at least to my knowledge), I just have a small "blue-screen" map which I made for the purpose of editing screenshots. I just add an alpha channel then "key out" all of the blue surrounding the characters, then add the background as a separate layer - of course, this isn't good at all if I was working with a blue character - but never having owned a blue character, it's not too much of a bother. :3
