2nd time: image/bmp on bmp

hi, how do you read cursor (x,y) 'under' extra images (drawn by
the same program). I have a map on the screen, and some pictures on
it, and I want that the program skips these pictures (cursor shows x,y
of map and copyrect shows areas of map).

The best example I have met is here: www.oziexplorer.com
and this demo program runs like I mean.