All good points. It wouldn't be unmoderated though. I'd likely set it up so that whenever someone uploads a banner, it's stored but not displayed. I'd be sent an e-mail automatically to let me know there was a banner that needed review, and I could take a quick look and approve/junk it. Basically, a medium amount of coding now to save me from annoying updates in the future.

I'm the type who puts little things off until I forget about them. If I get an automatic e-mail and all it takes is two clicks to check an image and approve it, I'll do it right away. If I have to spend 10 minutes making edits to a static page, I'll blow it off until later (and never do it).