A Raster is a Bitmap image (JPEG, PNG, GIF, etc.) that is made up of a grid of Pixels, such as a photograph or digital image.
They can be loaded into Trace, the Design Editor and Visualize.
How to Make PhotoShop Pictures Easier to Vectorize and Cut: Trace
Importing Vector Designs into Trace
Load File Image in Visualize
Load File Image: Trace
Loading Multiple Images: Images Tab
Pixels Per Unit: Images Tab
Raster
Raster to Vector
Take Picture: Trace
Take Picture in Visualize
Trace Vectorize
Vector
Vector Versus Raster Format
Vectorize Tab: Trace
Vectorize Image in the Design Editor: Opening Tab