Either you define 100 different bmaps and assign them to one (or more) panel(s) at runtime via:
my_panel.bmap = my_bmap42;

Or you could use "bmap_load": http://www.conitec.net/beta/abmap_load.htm
To load a new bitmap into an old bmap object.
Example:
Code:
BMAP* my_bitmap;

function load_NewBitmap()
{
  bmap_load(my_bitmap,"image02.tga",1);
}


hope this helps