Windows Users:

1. Choose desired wallpaper and size by clicking on your screen resolution. (i.e. 800x600 or other). A new window will open.
2. Wait for the image to load and right-click on it and select "Set as Background."

Mac Users:

1. Choose desired wallpaper and size by clicking on your screen resolution.  A new window will open. Wait for the image to load.
2. Click and hold on the image and save to your hard drive.
3. In your Desktop Pictures control panel, click "Select Picture" and choose that image.
4. Click "Set Desktop."