How about... we post wip in a wip gallery but with disabled comments and in forum  a link to that image? Just a thought...
I agree with have to come up with some kind of process that would suit everyone.

OT1. I would like to thank for your comments guys. You spotted things I didn't notice, and you gave me some cool ideas about my pic - thanks!

OT2. I noticed some critical comments under my wip coming from non memebers. I also noticed few honest comments in 'main gallery' from non members as well. I think it's great!