WHAT IF MY RESOLUTION ISN'T ON THE LIST?
There are hundreds of different screen resolutions, but over 90% of all users have their monitors set at either 640x480, 800x600 or 1024x768. If your resolution isn't one of these three, simply choose the one that's closest to your resolution and have your computer stretch the image to fit by doing the following:

WINDOWS: Choose "Stretch" from the "Position" drop-down menu when setting your desktop wallpaper.

MAC: Choose "Stretch to fill screen" from the drop-down menu when setting your desktop wallpaper.