4K HD Wallpaper: Hyper Car Pagani Huayra
Central piece in this 4K image is the Pagani Huayra, but look around :). If you like the photo can be downloaded under CC By-Sa license from courtesy of Ben. Here's optimized for apply on desktop backgrounds and homescreen phones.
Widescreen Desktop / Macbook (Retina): 2880x1800 (fits on: 2560x1600, 1920x1200, 1440x900)
High Definition HD 1080p: 1920x1080 (fits on: 1600x900, 1366x768, 1280x720)
Samsung Galaxy Tab & iPad: 2048x2048 (compatible with many tablets)
HTC, Samsung Galaxy & iPhone: 1080x1920 (compatible with many phones)