Multi-User Image Sharing CMS?

[Arekusandaa]

Hello there,

I've been looking for some time for a simple, aesthetic CMS that would allow one to create a multi-user image sharing site in the vein of Flickr or deviantART, but have had little success. Specifically I'm looking for something with these features:

1. Multiple users, each with their own gallery

2. Private messages and friend feature

3. Clean permalinks -- WP "pretty" style (e.g. www.site.com/profile/1213, www.site.com/artwork/1134)

4. Browsable categories (e.g. Photography, Sketches, Paintings)

5. Comments feature

6. User groups -- premiere membership, moderators

7. Admin panel able to manage all of these things

The permalinks and basic structure would actually be quite important. As examples, a piece of art might have as its permalink www.site.com/artwork/1212, while a user's inbox might be www.site.com/my/messages. Might anyone know of something akin to this? Thank you...