Photography software built into the Nintendo 3DS system. You can either take 2D photos with the internal or external cameras, or 3D photos with the external cameras only.
Once you have taken a photo, or saved one from a game, you can view it in your photo gallery and choose to edit it. You have pens, stamps and 3D effect tools for editing your pictures.
There are various other tools and settings available, and the helpful budgie is on hand to tell you all about them.