800 x 600 Wallpaper
Download Instructions For a PC:
Wait until the picture to the left has appeared on your screen completely
Right-click on the picture.
Choose "Set as Wallpaper".

Download Instructions For a MAC:
Wait until the picture to the left has appeared on your screen completely
Option-Click the picture, choose: Download image to disk
Save the image to a file on your harddrive
From the Finder, select menu item: Finder > Preferences.

Click on the "Select Picture" button.
Navigate to find your preferred choice.
Single click on your choice to highlight it.
Click Choose.