HD Wallpaper: Space Shuttle Endeavour
New unique photography from NASA's portfolio that can be downloaded free under CC0 license. Check it at full size to see if you like and download from here optimized for apply in desktop backgrounds and homescreen phones.
Widescreen Desktop / Macbook (Retina): 2880x1800 (fits on: 2560x1600, 1920x1200, 1440x900)
Samsung Galaxy Tab & iPad: 1996x1996 (compatible with many tablets)
HTC, Samsung Galaxy & iPhone: 1080x1920 (compatible with many phones)