As the title suggests, I am looking for a relatively simple open source solution to compare screen shots in a web browser.

Specifically, I have seen on several websites a software running I believe in Java that allows you to drag a bad back and forth across one image to wipe the comparison image over the top of it, which makes comparing specific features a lot more interactive than loading two huge images side-by-side.

Nvidia had something like that on their tweak guide I believe, but that might have been something proprietary of theirs...

Does anyone know of something like this that could be easily coded/uploaded to a website?

Sounds like this would be pretty doable with a canvas element and a multiple file element. Don't have the time right now, but if nobody posts anything, I'll get round to it later today.