Hashalbum is a photo discovery tool that scans Twitter for images and sorts them by their #hashtags, allowing you to find photos in a specific topic of interest.
If you're looking for a photo on a particular topic, chances are there are a few posted to Twitter. Hashalbum makes it easy to find these images by letting you discover new photos based on their #hashtag. For example, here's something I found in #tsa:
(Click to enlarge.)
To find what you're looking for, just enter a particular hashtag in Hashalbum's search box and it'll bring up any related pictures. It's simple, free and a good way to find topic-specific photos.