Did you even look at your link? He was measured at 6'11" in shoes for Team USA in 2013 and 6'10.75" a year later at the Hoop Summit in 2014, which was right before the start of Duke's season.
Also your pic is not a good one because of the fact they're wearing dress shoes, unless they both have on the same shoes height can vary wildly. Most importantly, look at how Towns looked next to Embiid -
His eyes line up with Joel's nose and Joel grew an inch after that pic was taken.
Karl at his size is a big PF, Okafor is not a big center at his size, he's the same size as Boogie