CompuServe Messages

So is it possible to display rez higher than this? Say, 800 x 600, or 1024 x 768. I suppose the only problem would by the encoder. If I create an animation that is 800 x 600 and can display and play that on my computer, the only limiting factor would be the encoder/converter—-it that correct? Is the screen value constant? Higher resolutions, which you suggest, implies that it isn't.