It's easy to start up a lively discussion among photographers, on the ethics of manipulating photographs.
Modern photography incorporates digital techniques now as standard tools.
In all of these it is the information in the image that is important, and image-workers will do whatever they can to bring out the information they are after. As a result there is a continuous spectrum of techniques that are applied to photographs, digital and otherwise. Many of us confine ourselves to one region of this spectrum, for reasons of personal taste or aesthetic and ethical sense. But my rules will bend depending on the purpose of the picture. I will leave the airplane trail in pictures like Deep Zumbra Sky and Platte Lake Trails .