Facebook photo zoom is one of the best utilities I have ever encountered when browsing a massive amount of photos. My question is how it was built, and if there is a free javascript application already written that mimics its functionality.
My initial search turned up a number of links on how it was a useful extension, but nothing detailing the underlying javascript. A similar programme can be found in FFixer.
If you look at the FB image URLs they are rather predictable. The mini-ones end in _q, then it gets larger with _n, etc etc...
You can make the effect however you wish, but essentially he just detects that the page is FB then on hover of an image with a certain class the image will get larger and replace _q at the end of the image with _n or whatever...
After that you can use a variety of techniques to present the image.