I need to be honest here... I really didn't know what an Artist Trading Card (ATC) was- and I still don't! All I know is that its about 2 1/2" x 3 1/2".... so that's what I made. Hope its correct! Made this to enter the Tiddlyinks Challenge #24.
Anyway, this is what I came up with... used the Tiddlyinks Annie's Card image that was a freebie awhile back. If you join their Papercraft Planet group, you can get freebies every month! Anyway, I thought Annie was cute and decided to use her for my ATC. Since these ATC's are so small, there's not a lot of room for much more than the image, so I kept it very simple.