It's reall fantastic picture lol
The upscale OneHuman has send wasn't blurry either but I declined it because the current picture is the author's original and we want to keep that one.
If you want a bigger version simply use our online resize tool or an image editor like nuubka did.
when you upscale it in photoshop is not even blurry....
http://i.imgur.com/inMOSQB.jpg - 1600x900
http://i.imgur.com/mjfHPVf.jpg - 1920x1080
People could just change their settings so that the desktop is filled.... But there you go. Blurry and 1920xsomething
Go and tell the artist to draw a bigger version then :P