HD Wallpaper: Canon 600D and Canon 1100D
This photography was made with an iPhone 5S by "Wyncliffe" (Flickr nickname). From his courtesy can be downloaded under CC0 license, so if you look for an image with Canon cameras check this one.
Widescreen Desktop / Macbook (Retina): 2880x1800 (fits on: 2560x1600, 1920x1200, 1440x900)
Samsung Galaxy Tab & iPad: 2048x1536 (compatible with many tablets)
HTC, Samsung Galaxy & iPhone: 900x1600 (compatible with many phones)