I read some good advices from the Cap'n and Mr. Ryves, including bypassing the PictureBox control altogether and using LockBits(). But if I am using a picturebox control, is there a way to manipulate the pixels of the PictureBox.Image without creating a new Bitmap every time (and setting it back, whatever that entails)? I know I can create a Graphics object, but it doesn't expose the naughty bits. So what am I missing?

If you have a Bitmap and assign it to a PictureBox's Image property, you can make a change to the bitmap and simply call the PictureBox's Invalidate method to update the image.