An obvious addition to the DS platform is the DSi's embedded cameras. Like most cell phones, the DSi handheld an external camera and an internal clamshell camera. This makes for easy picture-snapping.
The pre-installed camera software seems like bare bones image software stuff - things like altering images, changing colors, etc. There are some nice flourishes like blending two separate photos together and face recognition software. The face recognition software did have problems with recognition on several occasions, though.