When it comes to movies, you simply can't believe your eyes, no matter how realistic the image or situation. Spurred by rising computer power at lower costs and software that can reshape an image literally bit by bit, the digital-enhancement revolution is spilling over from F/X spectacles into the cinematic mainstream as unstoppably as that synthetic tidal wave in ''The Perfect Storm.'' It's not just a new tool for smoothing out flubs -- it's also a way to create settings and characters from thin air. And every year, technicians pound away at the limitations on what can be affordably fiddled with.

Here's a behind-the-scenes look at a few big movies that used digital doctors to solve problems, paint fantasy worlds, and, in some instances, devise remarkably realistic characters. --Steve Daly