HELP!!! Screen glitching HARD (pictures inside)

oh god oh god oh god...

full screen:

close-up:


doing @ time happened scrolling through google image searches article i'm writing. had multiple applications open including chrome, firefox, indesign, textedit, , excel, of computer has handled fine before.

while, able put sleep mode , when woke up, fine. shortly after that, however, screen went blank , replaced little white tiles couldn't take clear picture of. computer unresponsive, managed shut down holding power button, turned off frightened workhorse computer right now.

specs:
2011 27" imac
i7 intel 3.4 ghz
radeon hd 6970m w/ 2gb of video ram
12 gb ram
1 tb hdd

did have applecare on baby , did have corruption in screen while back, taken care of , covered applecare in 2013. applecare expired in may of year.

installed big firmware/software update on machine (through app store , legitimately) 2 days ago , maybe reason why i'm having problems right now, i'm not sure.

please, tell me there's easy fix and/or better soon. frightened right because workhorse computer , cannot afford loose now.

 

looks similar problem guy seems having

http://forums.macrumors.com/showthread.php?t=1832319

if it's same thing looks gpu toast, wouldn't panic yet i'm sure there better diagnosticians me who'll able out.

 

Forums Macs Desktops iMac

• iPhone
• Mac OS & System Software
• iPad
• Apple Watch
• Notebooks
• iTunes
• Apple ID
• iCloud
• Desktop Computers
• Apple Music
• Professional Applications
• iPod
• iWork
• Apple TV
• iLife
• Wireless