I think this one is very obvious, I'll share my view on it:
We've felt like this as children, when we've seen the bigger ones and adults from down below and had to bend our necks to look up to see their eyes. Bigger and older ones made us feel inferior, and we really were - back then. (*See also below)
Similarly, we felt superior to the smaller ones, and that's why looking from higher angle feels like being "superior" to the subject on the picture.
Both are for pictures displaying people, particularly faces, and of course - particular emotions on the faces reinforce this feeling. Like low angle and insidious laughing face, or high angle and face blinking with eyes or seeming confused.
I guess the stature stereotype is of the same origin - shorter ones are associated with "smaller one" - children, which is associated to own memories of being weaker and inferior to taller ones. I guess that's why in general short actors are more rarely the protagonists, especially superheros, than taller ones. (Another reason probably is statistics - taller, handsome etc. is more rare ("special") than ordinary).
By the way, it is not "spiritual", "collective unconsciousness", "archetype" etc. like other common phenomenons such as similar myths around the world. It's just similar conditioning, repeating experiences at different locations in similar/repeating circumstances, processed by similar generalization "processors".
* I'm not an expert in dog behavior, but I think this is related to the behavior of dogs. As little ones, they had to bend their necks up to see their mother's eyes, and this physically determined behavior is conditioned as a symbol of displaying inferiority or/and loyalty. Eventually dogs demonstrate similar body language towards their master/leader/provider (partially also for physical reasons - their heads are lower than ours, but not only - dogs try to look you in the eyes and come closer to your head).
More generally, I guess one of the discriminating skills of "social" animals is to be smart enough to understand and recognize those "providers" or "leaders", and to understand and "think" about inferiority and superiority of other agents, as grading expected benefits and dangers coming from them, which ultimately goes toward fight or flight decisions/reactions. This skill allow social animals to behave appropriately to maximize benefits according other agents (whatever benefit is for the particular agents and circumstances).
See Also: (Search: Nurture or Nature)