Every photograph is edited. Cropping, exposure, contrast and color balance are all normal, and they go back to the darkroom. The question is where normal stops.
Most news organizations follow a rule close to this: you can adjust the picture to show what was there, but you can’t add, remove or move things. The National Press Photographers Association’s code of ethics says as much, and so do the rules of major photo contests, which have disqualified entries over heavy processing.
A famous case
In 2003, Brian Walski, a photographer at the Los Angeles Times, combined two frames from Iraq into one stronger picture. Someone noticed duplicated figures in the background. The paper fired him. The image looked better, and that was the problem.
The gray areas
Is darkening the edges of a frame a lie? Usually not. Is removing a stray bit of trash? Many editors say no, since it changes the scene. Is a color grade that makes a sad day look golden? That one is harder.
A useful test is to ask whether a viewer, knowing exactly what you did, would feel misled. If yes, don’t do it, or say so in the caption.
Trust takes years to build and one crop to lose.