Set Custom Background Image?

I'm having a few problems creating a transparent form. The reason I want to do this is because I'm attempting to make a custom border (one that isn't exactly square).I can already get the form to be transparent, then I set my custom background image, which all works perfect, it even detects when the mouse enters the image, which is great. (I use transparency key to make the form transparent)

The problem is, if I add ANY control, or even if I just save the file, NOTHING else, the whole thing has a spaz attack.. Instead of having the image with the transparent form, the square form appears every time I run the app.