Just out of curiosity, I just made a form and set its autosize property to true. Then I put a panel on the form, and set its autosize property to true. Then I put a picture box in the panel and set its SizeMode to AutoSize. Then set the picture box's image to a 12 MP photo. Then I ran it.

The form seemed to be the same size as the photo at 1:1 plus the border. I was able to drag the form across the screen and see the whole photo -- about 4000 pixels wide. I can assure you, that is a lot wider than my screen. I couldn't drag it higher than my screen because I was dragging it by the title bar, but I bet I could if I made the whole form surface draggable.

There must be an answer to your problem somewhere in there!

bye, BB