The difference will be trivial. If you're generating your background image from within your program, you should consider that GDI will probably have better algorithms than you for doing this. Also if your form is resized, you'll have to recalculate your background at every resize. If the form is only displayed once, you'll take a performance hit from going to an outside file, or paging in the resource you're using for the background. (bigger executable = larger loading time). But again, this are trivial performance differences.. Since you're displaying a form, I suspect that you want some user interaction. The user won't notice the difference.