[id] = CopySprite(source, dest)
sourceand creates a copy of it as sprite
dest. If you specify Nil in the
destargument, this function will choose a vacant identifier for the new sprite automatically and return it to you. The new sprite is independent from the old sprite so you could free the source sprite after it has been cloned.
If you just want to have a new sprite with the same graphics
as your old sprite, you should use CreateSprite() instead;
it can create sprite links which are very memory-friendly, i.e. they
consume very little memory and thus should be preferred to