Gallery where users can upload their images

You can use gallery (http://gallery.menalto.com/), it’s a CMS for pictures. Lets you have users, comments, ratings, the whole deal.

And there’s a plug-in for wordpress, wpg2 (http://wpg2.ozgreg.com/index.php/Main_Page) that lets you have the gallery become a part of your blog.

They work pretty well together, and are pretty simple to set up too (it’s what I use).