An interesting article by The Wall Street Journal on manipulating photos delves into the accusations of tampering images to make them appear better. There has been some controversy about this for some time: composites from different photos put into one image; the removal of objects and people from the originals; and even claims of colours being doctored to change the end appearance.
My opinion is that nothing in of the composition should be changed at all, not even photos being cropped. The viewfinder for me is my canvas and the skill is trying to frame a piece of my surroundings to fill that canvas. Especially nowadays with the evolution of 4K cameras, it is so easy to point in a direction and snap away knowing that the subject can be cropped later for good composition. That to me is not the art of seeing when it comes to capturing great images on camera. It's akin to using an automatic machine gun and spraying a room with bullets instead of that one bullet sniper shot to do the same thing - timing and precision.
When it comes to colour manipulation, it's a different story. I personally do not like what some photographers are doing with HDR, but even back in the day of film there was always some sort of colour correction made in the darkroom. Even with B/W you had a choice of paper grades and developers to make the final image how you felt it should be. The heavy contrast images of Bill Brandt added to the feeling he wanted to portray, but took nothing away from the subject in front of the lens. Even, trying to match exact colours can be objective in different lighting conditions and a little more yellow can give it that feeling of a warmer day which emphasises the moment.
It will still be a contentious and controversial issue that will have differing points of view. Let me know what you think!