A photograph is not reality.....
Any photograph is a deviation from reality. We accept its flat, two dimensional nature, and that it has been selectively cropped; that you can't have a photo without this, or that we accept it, does not make it less of a distortion. Similarly we accept black and white photos as legit, even though taking all colour out of a scene is an extreme manipulation.
There is a story that a man once said to Picasso, "I'd like to show you my wife" and produced a snapshot of her, to which Piccaso responded, "She's very small, isn't she".
Things that are accepted imperfections of the optical side of photograph are also approved, such as lens flare, wide angle distortion of perspective, or the softness of the out-of-focus area of a scene (something present in our own vision, but usually avoided by our pinpoint attention and our brain). Some of these optical phenomena are actually used by some photographers for a purpose, as if, in our image saturated world, they have become phenomena in the natural world as well.
There are no rules here.
In a photo community I am part of, individuals sometimes describe a photo as "SOOC", which means Straight Out Of Camera, in other words, "this is one photo, believe it, I didn't mess with".
One of the key areas I like to adjust is the sky. I like to deepen the blue. I want the sky to somehow have a sense of mystery, to be somehow beyond the objects in the lower part of the picture. I love this dichotomy between the down-to-earth particular and the nameless unbound. This is what I feel when I look at a scene, that's the feeling I want in my photograph, and so I deepen the blue. If it's a black and white I can sometimes take it to something close to black along the top.
A photograph is reality......
And yet, even with all I've said, a photograph has power because we see it as a representation of the real. The sailor kissing the woman on VJ day in Times Square is an image with a significance no painting could have hoped to achieve, even considering that there is controversy about how spontaneous it was. It's as if we're looking back in time and experiencing that exact moment.
The photo collages of Jerry Uelsmann, combining straight images with solarized or negative images, have a fascination because they play with this real/unreal conflict.
I find myself creating two kinds of images. One is the obviously manipulated, such as the photo above. With the other kind of image I may take liberties with the appearance or content of the photo, but I am not happy if the photo does not look real, something anyone would feel they could see in their own world.
As a photographer, I warn you that any of my photos that you view have without doubt been manipulated. How and to what extent is my concern. How real they are is something I'll let you worry about.