Art cards or miniatures were sold in 16th century Europe and later used as advertisements by artists and photographers. The modern Artist Trading Card (ATC) is a 2.5″ x 3.5″ card made specifically for trading. The ATC movement was started in 1996 by Swiss artist m. vänçi stirnemann when he created 1,200 cards to document his own work. These cards were exhibited in April/May 1997 in his Zurich bookshop, where he invited visitors to create their own cards to trade with him. The original ATC philosophy spoke against the commodification of art and the hierarchies of the art establishment, and encouraged more democratic forms of art-making.
More on ATCs.
Will trade ;).