@AsphyxiatingArrogant sorry for the late reply ^^'
You see where your picture is, the small one in the very top which has your username next to it?
There's a small arrow pointing down, don't click it just hold the cursor over it.
Alot of options will show, just scroll down to settings and click it.
Your edit page will show. Here you can change many stuff. Go to the right and you'll see your background and profile picture. There you can browse any image you have saved. Then just save changes, go to you profile page and done, you'll see it :D
Hope it helps :)