These are the normal decktet cards resized so that when you upload them to printerstudio.com, they will fit perfectly within the cutoff lines. I have included an original card back that was made by HenryBlatbugIII found at http://www.boardgamegeek.com/image/866761/henryblatbugiii
If you want to use a different backing, simply resize any backing image's canvas size to 110% and center the image, then upload.
If you have any questions, feel free to ask.
I'm just glad to help.