Of Course like plendej said, you can use BitBlt (for faster result of course) but your are limited to 1:1 drawing.

If you don't like Api, you can use the PaintPicture Methd from the picture box. It's something near BitBlt (a bit less effiency, but barely noticeable) but it can stretch pictures, copys part of pictures etc. And The BEST part of it is that is will be "reconize" by the picture box.

If you use BitBlt to Blt the picturebox some functions of the pictures box may not be working properly (it's said in the msdn) so by using PaintPicture, it's totally compliant!