If im reading right, you want to use a background and have your stick-figures on top of the background correct? If so, I think its best you look into getting photoshop. You could do layers on top of your BG and edit + move it whever you want. Once you play around with it and learn how to use it, itll work wonders for you. MS Paint is okay, but I would never use it for editting, it sucks at it; all you could do is view images with it. I hope that solves your question...