destroy_bitmap (3) - Linux Man Pages
destroy_bitmap: Destroys any type of created bitmap. Allegro game programming library.
NAMEdestroy_bitmap - Destroys any type of created bitmap. Allegro game programming library.
DESCRIPTIONDestroys a memory bitmap, sub-bitmap, video memory bitmap, or system bitmap when you are finished with it. If you pass a NULL pointer this function won't do anything. See above for the restrictions as to when you are allowed to destroy the various types of bitmaps.
The bitmap must not have a mouse cursor shown on it at the time it is destroyed.