Some speculation in the thread about whether or not it's JPG artifacts, but if you make it to the 2nd page (post #21) someone included some information proving

Some speculation in the thread about whether or not it's JPG artifacts, but if you make it to the 2nd page (post #21) someone included some information proving it's intentional: http://www.ownedcore.com/forums/world-of-warcraft/world-of-warcraft-general/375573-looking-inside-your-screenshots-2.html#post2489452 http://www.ownedcore.com/forums/world-of-warcraft/world-of-w... Edit: Page 6 includes confirmation from a (supposed) Blizzard representative that this is for NDA leak tracking: http://www.ownedcore.com/forums/world-of-warcraft/world-of-warcraft-general/375573-looking-inside-your-screenshots-6.html#post2493282 http://www.ownedcore.com/forums/world-of-warcraft/world-of-w...