What is photoshop tennis?

Photoshop tennis is a competitive sport that has evolved on the Internet utilising Adobe Photoshop or similar graphics editing programs. It is normally a game for 2 players, though doubles matches and any number of players are theoretically possible. The players pick a starting image, then one player makes some sort of alteration to the image in any graphics manipulation package that they like. They then send their altered image, usually via email, though posting the image to a Photoshop tennis forum is another possibility, to the other player, who then edits that image and sends it back to the first player. This process goes back and forth until the number of rounds that they have previously decided on are over. When the final round is over, an independent judge determines who played the best shots, and declares that person the winner. Sometimes extra rules can be enforced such as sticking to a particular software package, or keeping the images to a theme.