A popular homebrew DS application, Colors, has become a commercial project available for iPhone, Java, and now, Nintendo 3DS!
Their Java version, ColorsDraw, is available for free on their downloads page, while the iPhone and 3DS versions will run you about $7. The iPhone version has a "Lite" edition so you can try before you buy, but the 3DS version has no such demo.
While the price may seem high for non-artist types, Colors! is a very nice tool for artists on-the-go. The old homebrew DS version was great, and the new 3DS version is most likely even better! For $6.99 ($7.64 after taxes), it is a brilliant, portable canvas drawing and painting tool.
- Very easy, fast-paced layer-switching and zooming.
- Extra features: coloring book and painting samples.
- Eyedropper, pan, and opacity tools make drawing fast and comfortable.
- 3D effect looks cool sometimes.
- 3DS has no pressure sensitivity. Original DS does.
- No resolution options, just 3 canvas-viewing options. Size of image does not change.
- Bottom screen is only one you draw on, and that screen is very small.
- No undo!
There is a photo reference feature that allows you to snapshot a photo from either the front or back camera. The back camera option only uses a single camera, not both, so 3D pictures are not supported. You can, however, import pictures, but they are still single images, not capable of the 3d effect. Pictures can be used as backgrounds, references, or overlays.
Here is an example of a photo taken by Colors with the back camera, used as a background image for a spooky drawing: LINK
The biggest flaw in my opinion is the lack of an undo option. If I make a mistake while drawing, I basically ruin my previous work. Considering I only get 5 layers to work with, the lack of undo is extremely unfortunate.