The Add Bitmap function allows you to add standard Windows bitmaps to your designs. There are, however, some limitations on what you can do with them.
Bitmaps can be added to the design on any layer. You can then print or plot them out on any standard Windows printer by selecting Windows as the output device.
However, bitmaps cannot be output to Gerber plot files. This is because bitmaps are 'raster' (dot) images, and Gerber is a vector ('line') format. There is no way to represent bitmap images in Gerber files.