Someone will post a picture, and the next person has to post a different picture that descibes the first thing they think of when they see the picture. Basically word association but you post a picture instead.
No double posting.
Nothing that breaks any forum rule
No huge wallpaper sized pictures. Limit it to 800x600 at the very most. Resize if you can to make it fit better.
If its not a clear link, or you want to explain why you choose it, do so!
First picture is: