Tagging, and perhaps the ability for it to scan existing threads and posts for images that can then be added somehow?
We've been running without a gallery for quite some time now (used to run Photopost, and that's still saved in the database), so all our images have been uploaded into threads.
Would be great somehow being able to dump those into a new gallery, assigned to the uploading users, with perhaps an alert for them to categorize them properly?
Definitly integrate new images into "Recent Activity". Add trophy points for uploading of images.