Each frame in a Springboard file is made up of layers. If you have used other graphic editors, such as Photoshop, Illustrator, Corel Draw, or Paint Shop Pro, you may already be familiar with the layer model. If not, you can think of layers like pieces of paper that are held together in a stack, with the following properties:
The layers in the current frame are shown in the Layers palette:
There are two basic layer types: bitmap layers, that contain a grid of colored dots ("pixels"), and vector layers, that contain a "vector object" that can be changed at any time, and which converts itself to pixels whenever it is drawn on the screen.
Springboard's drawing tools work with either bitmap or vector layers, but not both. The "natural-media" tools draw onto bitmap layers, while the vector tools create new vector objects on their own layers.
Some quick tips and links on working with layers: