i would show u but i get yelled at for showing that site so i'll show you something else. Its called TinEye its a reverse image search site.
you can take any picture and find others like it its great for when people post screenshots and you want their background but not the other crap (icons, etc...) in the image.
Here's the background you want
is the site for you to use if you ever find one u like in the future