That looks like fermentation to me, and I have had a beer go that long. The only way to be sure that fermentation has stopped is to take sequential measurements of the gravity over a period of 2-4 days. If the desired fg has been reached, and you want to stop further fermentation, dropping the temperature would accomplish that.
The infections that I have had, have looked more white and powdery in a way.
I love this picture...it is just grose