To save, right click on the image size below and choose 'Save as Wallpaper' alternatively you can click 'Set as Background'.

Choose the wallpaper that suits your screen - Don't know your screen size? View your resolution 

Choose from:

640 x 960 (iPhone 4)
768 x 1024 (iPad 2)
1280 x 1024
1600 x 1200
1920 x 1080