I've seen in most programs the following use:
wndclass.hbrBackground = (HBRUSH) GetStockObject (WHITE_BRUSH) ;
My doubt is how can I set the background as a image that I created and build my application based in that image.

I know that is possible once I've seen many programs with customized interface like WINAMP.

I don't know if is the way. Hence I would like to know how this is made.