The only way to search for images on Facebook is through tags, which is a) a clumsy way to search, and b) only good when you're looking for photos of people. What if you need a photo of the Taj Mahal, or of a red boat?
How does it work?
GazoPa Book doesn't really fix any of this, but it does give an additional, interesting way to search (or, better put, stumble) for images on Facebook. You can install the application here (click on the title). Initially, it'll display several photos similar to your profile photo, to one of your friends' profile photo, and to some photos from your photo albums. Hitachi's technology analyzes the shapes and the colors on the photos and brings you similar photos based on this information.
It works well in some situations, especially when it comes to analyzing colors; in other cases you'll just get a bunch of random photos which perhaps bear some resemblance to the original photo, but probably not enough to be useful in any way.
You can add the application to your profile as a box, but it can only be used there as a gimmick: it merely displays several photos similar to your profile photo.
The only way to really use the application for search is to open it and click on the "all friends" or "all photos" link next to the title of each photo group randomly chosen by GazoPa Book. Then you'll be able to browse through all the photos in that particular album. Clicking on "more" next to each image group will give you more results directly on GazoPa's site.
Usefulness and one extra Facebook hack
At its current state, GazoPa Book is not very useful. The inability to choose exactly which photos you want to start your search with is annoying, and the entire interface is clumsy. Currently, it works only as a gimmick or a proof of concept; hopefully the application will get better after some updates.