After getting an answer from The stoffe in the badge recommendation thread, I'd like to suggest
Ahto's avatar/signature thread for revision as there are a lot of members who've definitely earned the helpful badge for their contributions there. From checking the last five pages, I can name Rev7 and Thanatos9t, but there are 25 more pages and surely many more people who've contributed significantly with their picture editing skills and they shouldn't go unrewarded.