To set on desktop:
Windows: Determine your screen resolution by going to the start menu, selecting "settings," then "control panel." Open "Display," go to "setting," the "Screen Area" is your screen resolution. Click on the appropriate link for your resolution. When the image has loaded, click the right mouse button and select "Set as wallpaper"

Macintosh: Determine your screen resolution by going to the Apple Menu, then "Control panels," then selecting "Monitors" or "Monitors And Sound" of "Appearance". The highlighted dimensions under "Resolution" is your resolution. Click on the appropriate link for your resolution. When the image has loaded, hold-click until the menu appears. Select "Save image to disk." Go to the Apple Menu, then Control Panels, then Appearance. In the Appearance panel, click on Desktop, then click the "Place Picture" button. Choose the picture, then click "Set Desktop."

If you are using a different screen resolution then please select the closest option.