Like the photo section of the built-in AR Games, you can use special cards to take pictures with Mario characters in them. Want a photo with the main man Mario? Take a picture. Want to stomp a Goomba? Take a picture of you jumping off the couch onto one. Have a crush on Peach? Take a picture of you holding hands with her. That's not creepy and depressing at all.
The game is meant to be used with special $10 eShop cards that are available at Target. So you get $10 in eShop credit and the special card. Sweet!
Or, you can thank your good buddy Me for providing the pictures below, which can be printed and cut out and used just the real thing.
Only the Mario, Goomba, and Peach cards are available so far. The other three were available in Japan when the app released, so hopefully we see those soon, as well. Japan also received Animal Crossing and Pikmin photo apps. Here's hoping we eventually see those as well.