I used to participate in PhotoShop Tennis games at the Sitepoint forums around 2002.
What is 'PhotoShop Tennis'?
"Photoshop tennis is a game played through sequential alternating photoshopping of an image.
Each match of Photoshop tennis is generally played with two competing players, though doubles matches, as in the sport tennis, or other multiplayer matches are theoretically possible. The players pick a starting image, or one is "served" by a player, then another player makes some sort of alteration to the image in any chosen image editor (matches are not exclusive to Adobe Photoshop). He or she then sends that altered image to the other player or players, usually via e-mail or by posting the image to a Photoshop tennis forum, who then edits that image and sends it back to the first player. This process goes back and forth until a predetermined number of rounds have elapsed, or the players otherwise wish to end the game. When the final round is over, there may be an independent judge who determines who has played the best shots, and declares that person the winner, or players may play without a clear winner. Sometimes extra rules can be enforced, such as sticking to one particular software package, or keeping to a particular theme."
Photoshop contest. (2008, January 20). In Wikipedia, The Free Encyclopedia. Retrieved 18:01, February 20, 2008, from http://en.wikipedia.org/w/index.php?title=Photoshop_contest&oldid=185699378
The games I played were strictly using PhotoShop and I hosted by PSD serves here, so the other players could have easy access to them withouth having to deal with possible email size restrictions.
If you followed an old link of the form jaelin.com/tenis/filename the file can now be downloaded from jaelin.com/files/tennis/filename