Compiled sprites are stored as actual machine code instructions that draw a
specific image onto a bitmap, using mov instructions with immediate data
values. This is the fastest way to draw a masked image: on slow machines,
up to and including a 486, drawing compiled sprites can be about to five
times as fast as using draw_sprite() with a regular bitmap. On newer
machines the difference is usually negligible.
Compiled sprites are big, so if memory is tight you should use RLE sprites
instead, and what you can do with them is even more restricted than with RLE
sprites, because they don't support clipping. If you try to draw one off the
edge of a bitmap, you will corrupt memory and probably crash the system. You
can convert bitmaps into compiled sprites at runtime, or you can create
compiled sprite structures in grabber datafiles by making a new object of
type 'Compiled sprite' or 'Compiled x-sprite'.