Just a thought, regarding the representative function of portraits. The change is especially visible in ruler’s portraits. Take e.g. the Doge of Venice by Bellini, 1501:
Presumably as with other portraits of this kind, copies were put up in official buildings all around the country. So that the Doge would always be present. This way, one person can be in many places at once. And exercise authority.
Nowadays this, too, has been democraticized. With the automatic synchronization of biometric face databases, we’re all everywhere, anytime. Except that the power relations have changed, too. It’s pictures of those that need to be controlled and disciplined, that are being exchanged.
Those pictures are normally not put up on a wall (except maybe when you’re on the most wanted list). So what is it that happens exactly, when no human is looking at those portraits, but algorithms. What is being done to the representation of you?