For GSL we wanted a tool to offer image annotation support, we found fotonotes (which is a hardcore overkill imho) and after that we found jQuery Image Annotation plugin by Chris.
Unfortunately the plugin had no support for PHP api, so I said to write it.
I wanted also to test my github account for long time, so this was also a good reason to do that, although, I might be back to my code.nerd.ro repository.
Check it out on GitHub, fork it, and I hope it will get merged into the upstream version, cause I don’t think I’ll get time to support/improve it.
:)