MySims Camera is more of a photo editing tool than a game. The "game" lets you edit your DSi photos by using MySims characters.
You can edit two types of photos: ones that you've already taken and ones that you're about to take. Many tools are offered to you to modify your picks. The game's selling point is the fact that you can put the MySims into your photos. You select which Sim you want to use as well as his or her animation. These animations can vary from waving to sitting down to making a pizza. You can select the size and orientation of your Sim. You can also pause their animation and place them wherever you want on the screen.
The game also gives you the editing tools that you've come to expect from a photo editing tool: a pen, an eraser, stickers, etc.