Some interesting thoughts.
There isn't really a right answer on the original question. Most people assume photographs capture a 'real' image, but that's just not so. Neither film nor sensors can see as much in a scene as the human eye can. They just can't capture the very darkest and very lightest details. And the interpretation of color is never perfect. Since the beginning of photography people have grappled with these problems, and we still are.
With film, you made and exposure and kinda had to live with it. You could tweak things when the print was made by varying the amount of light that hit the photographic paper. You could darken or lighten portions of the print by increasing the length of time light hit a certain part while shading another part with a mask, and vice versa. Different film types had different contrast and saturation properties. 'Kodachrome, gimme the nice bright colors...' was talking about just that. If you shot film, you could get a lot more saturation with that, or Fuji Velvia and Reala. If you shot under incandescent light, you bought another film, or suffered the yellow cast with no way to fix it after the shot. If you had your prints made, you likely had a machine try to adjust it to 'average' when it printed, rather than just take it as it saw the negative. And, remember, you had a meter tell you or your camera how to expose it anyway.
Today's sensors are a huge leap forward. The dynamic range (range from darks to lights) are expanding. The sensitivity is increasing exponentially (The top of the line Nikon digitals get 125,000 ISO equivalent; I remember being excited with 400 film) The White Balance allows shooting in all kinds of light from sun to incandescent to sodium to florescent.
Photographers have been doing things to make the picture look better all along. Not better than reality -- better than the technology could reproduce. Ansel Adams himself looked at the negative and the print as two separate processes, comparing the negative to a composers score, and the print to the performance. Sooo much room for interpretation in the 'performance'.
Great photographers have many of the same skills of great artists. They know composition, pattern, light, color, all that stuff. A great photograph has the elements of a great painting. They are truly art. If you see a photograph and you kinda think, 'Wow' and it makes you want to look at it, you've encountered a great photograph. Whether it be a spectacular moment in time, a beautiful scene you wish you could step into, or anything else that stimulates emotion...that's art.
When you understand what makes a great photograph, you appreciate it more. I see 'neat' stuff all the time...things that tickle that 'Wow' button. But, I know enough to see whether it's pure trickery (usually) or a dedicated photographer that put in the time to catch the subject at the perfect moment in time, compose it correctly and get the technical part right. The phony stuff usually exposes itself in one way or another. So, I'm fairly comfortable I can discern between a photoshop creation and a photograph. But not always!
When you significantly alter the reality of a scene that is presented as reality, I think there's an obligation to disclose it. I would. But not everyone will -- and you should be a little skeptical if your brain tells you some photo is absolutely AMAZING!