I know what you mean! You 'look at' static photos' or you 'see' them , if it is a voluntary action and you can 'watch' them as well,but in the sense of attentively looking at them or closely observing them. 'Watch the photo' means look carefully and observe its details. As for 'dynamic photos' you will be watching them as in watching a movie! In the sense 'of guarding or tending' you can 'watch static objects' as well !

Yes. If you move along the dynamic object and keep yourself and the two objects in a straight line.

Why not? I mean, why do you think that would be impossible?

Next time be precise. No need for smart ass abstract stuff. No, you cannot watch photos. Unless the photos get up ad do something, as in Harry Potter. However, you can watch a person who is standing still. When you are watching, it means you are expecting something to happen. That would not be the case with photos.