Funny you should ask! That little blue/green eye that's used in the demo was the logo for "PictureDiff". I took out all the heavyweight stuff, and made it just a filmstrip, and you could click images in the filmstrip to open diffs. It also had the ability to compress images using diff: you compare a JPEG quality 50 image to a quality 80 image to decide if the extra filesize is worth the extra quality.

I spent $100 on AdWords to get people to look at it, but not a single visitor liked the site enough to download it. I might have given up too soon, but I decided to scrap it. I was way more motivated to tackle the general diff problem, and I didn't want to put a lot of effort marketing something I wasn't excited about.