What I write here is a description of what I have come to understand about photography, from photographing and from looking at photographs.
A work of art is that thing whose form and content are organic to the tools and materials that made it. Still photography is a chemical, mechanical process. Literal description or the illusion of literal description, is what the tools and materials of still photography do better than any other graphic medium. A still photograph is the illusion of a literal description of how a camera saw a piece of time and space. Understanding this, one can postulate the following theorem:
Anything and all things are photographable.
A photograph can only look like how the camera saw what was photographed. Or, how the camera saw the piece of time and space is responsible for how the photograph looks.
Therefore, a photograph can look any way.
Or, there's no way a photograph has to look (beyond being an illusion of a literal description). Or, there are no external or abstract or preconceived rules of design that can apply to still photographs.
I like to think of photographing as a two-way act of respect. Respect for the medium, by letting it do what it does best, describe. And respect for the subject, by describing as it is. A photograph must be responsible to both.