It happened to me only once, I was working on an a project with Photoshop. I spent many nights on it and once it was finished, I saved it. Well, the next day when I wanted to do one more thing to it, it was corrupted and the art work was just a mess of horizontal colors. Rawr!!! Ever since then, I just make sure that I have a back-up. I guess one of the layers went sour.

I'll clear my browser caches and check your site again. I downloaded some extentions for FF, so I can check into it further to make sure nothing else is wrong.