I'm beginning to lean towards a forum model for the following reasons:

1. It allows a dialogue between creator and critics, including the ability to show revisions to the work. We probably want to work out the protocol about whether we want to link to the gallery for the newest version only, or (possibly wasting bandwidth) upload WIPs inline. This would have been very useful for me in my most recent image since I've been having some technical difficulties with it.
2. It allows us upload works to our galleries without the implicit desire to have them criticised. (I don't mind criticism on any of my images, but some of them are just toss-offs, and I don't want people to think that they have to spend a lot of time thinking about them.)

A couple of things to consider as a forum:

1. Since there will be a lot of images, we may want to delete or archive threads after they are inactive for a long time.
2. We probably want to have a single thread per image.
3. We need to be careful about labeling threads with content advisories.