The development team for JoomGallery has a CB plugin that links users in CB to images in JoomGallery (basically, "tagging" users in images).
They've recently opened up development on the project, placing it on GitHub - I didn't see an announcement of the move here on the CB forums, so I wanted to share it here for everyone, especially people who might be able to contribute some code.
Here's the link to GitHub:
github.com/JoomGallery/jg-cb-tab
Thank you for your contributions and help!