help needed with Frames

Im not sure any ofyou can help me or not but im gonna ask and see. I have a web site at www.geocities.com/~baclan and I use frames for 3 years ago. I keep seeing pages like http://www.westwood.com/games/ccuniverse/renegade/index.shtml
where you add one gif at the top left in one frame and you add another at top left in the main frame and they meet to make one gif. When I try to do this i get that scroll bar between the frames. I know this sounds stupid but try to bear with me. Any idea where I turen to find this info out?

Shannon Thomas