I somehow doubt it. Something changed in some recent GO where the still image seems to be a poorer quality jpeg or thumbnail than prior versions. The video screen image, as you found, is a lot sharper also on my iPad Pro than the still camera shot too, but off the SD then it is better. Might be they wanted to keep the app to consume less resources so they downgraded the screen quality in a sacrifice for speed and less image breakup on the screen as the larger still images may be a larger thumbnail jpeg than off the smaller movie frame still which eats into the screen GPU speed.
My two-cent early AM theory.