The digital manipulation by The Economist for its cover, left, of a news photo taken by Reuters photojournalist Larry Downing, right, is a recent example of the ethical challenges posed by imaging technologies.

Since the advent of digital photography in the early 1990s, there have been hundreds of cases of manipulation of news photographs by newspapers and magazines for editorial, artistic and cosmetic purposes. The practice, of course, preceded Photoshop and its competitors: Airbrushing, touchups and other forms of darkroom sleight-of-hand have been in use for decades, especially at magazines. But the arrival of digital photography software in the newspaper industry and at the consumer level introduced a new set of ethical questions within journalism.

The current debate over the use of an image of President Barack Obama at the Gulf of Mexico, with an oil platform in the background, is only the latest. In it, a cover version of the Reuters photo, manipulated by The Economist, has local resident Charlotte Randolph digitally scrubbed away, while another figure in the original shot, U.S. Coast Guard Adm. Thad W. Allen, was cropped out.

An article yesterday by Jeremy W. Peters in The New York Times cogently presents the arguments for and against such treatment. It’ll be a good case study for discussion at my journalism ethics class at the University of Western Ontario tonight. Reuters, meanwhile, has issued a statement saying the edit at The Economist violated its policy.

For a good summation of the view commonly held in newsrooms, both in Canada and the U.S., see this essay by photographer Frank Van Riper in The Washington Post.