Nintendo launched Photos with Mario on the U.S. 3DS eShop today, an augmented-reality camera app.
The free program lets players pose 3D models Mario characters like the plumber himself, Peach, and a Goomba in real-world scenarios using the 3DS camera. Players can arrange multiple characters in a single photo using special AR Cards, blow on the screen to make them strike a pose, and take photos with a timer. The AR cards come packed in with $10 Nintendo eShop cards available exclusively at Target. Or you could print them out from this AR Cards Database listing - which also seems to be the only way to access the Koopa Troopa, Luigi, and Bowser cards outside of Japan at the moment.
Photos with Mario is separate from the AR Games app and cards which come with every 3DS system.
Nintendo has not announced any plans to bring the app and its special eShop cards to Europe.