After the better part of 15 years spent struggling with the concept of what is a photograph?, I have arrived at some conclusions which, despite the gazillion words written and expressed on the subject since the very inception of the medium, are really quite simple ...
1. a photograph is a picture.
2. virtually all pictures, created with photography apparatus, are a cohort / representation of a referent found in the real world.
3. a photography-created picture is best experienced as a printed object.
4. the print is a thing in and of itself, independent of that which it depicts.
5. inasmuch as a photography-created printed picture is considered to be part of the visual arts, it should be addressed, first and foremost, as a visual experience.
6. while a photography-created printed picture can be appreciated for the depicted referent, the best photography-created printed pictures can also be appreciated for visually preceived qualities with which the picture has been constructed.
7. pictures which are created / constructed employing good visual qualities - visual energy (agitative or placid) and rhythm (cordant or discordant), regardless of the depicted referent, are those which have the best chance of being hung on a wall and appreciated over very extended period of time.
8. looking for meaning in a photography-created picture is an illusive pursuit inasmuch as there will be as many meanings as there are viewers.
9. nevertheless, inasmuch as interperative meaning is subjective (except for pure propaganda), a given photogaphy-created picture may incite a deep / powerful meaning for a given viewer.
So there you have it and it's not that complicated. Except, of course, for the "visual energy and rhythm" thing. The so-called rules of composition rarely, if ever, apply to the creation of visual energy and rhythm. Creating such qualities is more of a feeling / intuitive thing and I am not certain that it can be taught. Rather, I believe that in most cases it can be recognized in one's pictures and subsequently fostered in continued picture making.