I'm trying to use some graphics which I drew in paint then imported into my resources in visual basic 2005. I want to display the images in pictureboxes

I am having trouble get the program to recognise the background of the images. I cannot seem to set them to some sort of transparent or default colour that will be ignored. White comes out as white, drawing as opaque (until the image menu) doesn't seem to help.

Alarmingly, Visual Studio has crashed a few times while I've been trying to edit the pictures...

Anybody know the process to set the background to default/opaque/transparent? If need be, I can recreate them from scratch (they're fairly small), I just want it to work.

Edit: I'm using bitmaps if that changes anything (but I don't need to)