I recommend this bmx gui tutorial: http://www.blitzbasic.com/Community/posts.php?topic=54579
It is impossible to load images onto normal windows buttons.
Though you can you a listbox or toolbar.
Or you could use an image canvas to create your own "button(s)",
Depending on how big your level is, you'll probably need a scolling canvas. Means you display the level with a virtual "viewport" which is scrollable. The technique is also explained inside the tutorial:
http://www.2dgamecreators.com/maxgui/T13-Sliders.html
It is impossible to load images onto normal windows buttons.
Though you can you a listbox or toolbar.
Or you could use an image canvas to create your own "button(s)",
Depending on how big your level is, you'll probably need a scolling canvas. Means you display the level with a virtual "viewport" which is scrollable. The technique is also explained inside the tutorial:
http://www.2dgamecreators.com/maxgui/T13-Sliders.html