How about a Flickr group?
They've got an easy bulk upload tool, tagging, group-only search and free accounts can upload 100MB per month. Not sure about downloading bandwidth, but I'm sure we won't overwhelm Yahoo.
I created a group here, if you want to test it out:
http://www.flickr.com/groups/313567@N24/
I threw up my Buffalo Wings logo to test it out...
What do you guys think?