Here you go: https://i.minus.com/ibqw7cpkxU2Jm.png
Alternate version with film grain effect (dithering): https://i.minus.com/iBiI0oqwXgF39.png
I used SmillaEnlarger, an open source image enlarger.
I like making wallpapers from league splashes and am faced with the problem of blowing them up to UHD (so they look nice on my monitor), and the best way I've found to get around it is to use an image enlarger, or not use the entirety of the splash so the tearing/alpha lines are not as noticable.
They still look good though, the software i've been using is Smilla enlarger, it's free and does the job really nicely.
http://sourceforge.net/projects/imageenlarger/
You get a better result if you enlarge the living fuck out of the image; then reduce it in photoshop to the desired end-size. You might be better off if you adjust the brightness/contrast first.
A nice underrated service is the program FotoSketcher. It converts your pictures into oil paintings, watercolors, pencil sketches, etc. http://download.cnet.com/FotoSketcher/3000-12511_4-10767783.html
Another underrated service is the program is SmillaEnlarger, which enlarges pictures while minimizing distortion. http://sourceforge.net/projects/imageenlarger/
Both programs are free!
Screenshot from Portal. Edited with FotoSketcher. http://i.imgur.com/gFTzh.jpg