Marginal art, which can be called the democratization of art, is superficially regressive in the sense that it is derived from specialists such as inventors and researchers, in light of the original fate of photography.
However, the fact that in the process of evolution of photography from the early production techniques to the present day, when digital technology has reached its peak, the vector has shifted from some specialists to general enthusiasts, and even to those who are familiar with photography as a part of their daily lives, tells us the "position (concept position)" of what is called marginal art.

Therefore, if the art that is intended to be acted from expert to expert is pure art, then the early works that consider "photography" as art can be classified as pure art "at that time (point in time).
They could also become popular art in the sense that they acquired their concreteness by spreading to the masses.
However, by going further, as represented by Instagram, photography has acquired a level of affinity that allows it to snuggle up to people's lives.
Ironically, as an essential point of arrival, we are at the point where marginal art aims to be.

This is only because photography, by its very nature, translates all experiences into images, and thus has the destiny to be equally captured by diversified values.