>i want to make a program that uses a map of a country. when clicking on a town i run an action.
>how can i make different departement or town of the map active on a bmp image ?

You can put a transparent background label control on top of the section you want to activate with a click, and the write a click method to it.

I've seen map solutions where the developer used bulletin-board-tack-icons with tansparent backgounds to indicate where the user could click to get the desired action.