Why is my Macbook Pro 2011 video garbled after sleep?

It was bad memory. I had upgraded to 8GB, but at some point suspected the memory for some other problem, so put the original Apple 4GB back in. Both problems went away (tested for 3 months) so I ditched the 8GB and got 16GB of higher quality memory that more closely matched the timing specifications of the original Apple memory.

So far, after two months, I haven't seen this or the other issue yet. So in this case it was bad (or wrong) memory.

Definitely take it to an Apple Store if you have one close by. Even if you can't reproduce it right then and there, show them the photo above. It might be a hardware problem (loose connection, faulty graphics chip, etc.), so you'll want to get it looked at by a professional.