Ken Irby, Poynter:
The Times has very clear guidelines in place that prohibit image manipulation without clear cause and disclosure:
Photography and Images.
Images in our pages that purport to depict reality must be genuine in every way. No people or objects may be added, rearranged, reversed, distorted or removed from a scene (except for the recognized practice of cropping to omit extraneous outer portions). Adjustments of color or gray scale should be limited to those minimally necessary for clear and accurate reproduction, analogous to the “burning” and “dodging” that formerly took place in darkroom processing of images. Pictures of news situations must not be posed. In the cases of collages, montages, portraits, fashion or home design illustrations, fanciful contrived situations and demonstrations of how a device is used, our intervention should be unmistakable to the reader, and unmistakably free of intent to deceive. Captions and credits should further acknowledge our intervention if the slightest doubt is possible. The design director, a masthead editor or the news desk should be consulted on doubtful cases or proposals for exceptions.
Here.