Instructions: Click on the size that best fits your desktop, wait for the photo to download, then right click on the photo and select "Set as Background."
Mac users: Click on selected image and drag onto your desktop (or hold down mouse button over image link and save file to desktop).
Hold down the Control button on the keyboard while clicking on an empty area on your desktop.
Select "Change Desktop background."
Find the philly.com wallpaper image you've just downloaded and click on it.