Aspect Ratio and Viewable Area - How Computer Monitors Work | HowStuffWorks
Everytime I start up tf2, the background of my pc changes quickly to this, presumably to change the aspect ratio fit for tf2. It always goes back to the normal aspect ratio,
Aspect Ratio | What you need to know for your Digital Display
Windows 10 tip: Create a perfect background for your desktop or lock screen | ZDNET
Monitor's Aspect Ratio-How to Determine It?
Windows* Desktop Appears Smaller than My Display Screen