Every picture tells a story, sometimes the wrong one.

An article in the December issue of Nature Medicine gives a straightforward account of a recent apology by the BBC (PDF). In 2004, the network ran the AIDS documentary Guinea Pig Kids, which is about the treatment of a group of HIV-positive foster children in Harlem. Today, the BBC says Guinea Pig Kids does not stand up to its journalistic standards.

Not so straightforward is the photo accompanying the Nature Medicine article: In the foreground, a black toddler stands in a crib, one of nine paint-chipped, closely packed cribs occupied by other toddlers. Although the caption is vague—"Foster children took part in trials of AIDS drugs"—the context of the photo suggests that it somehow documents the HIV-positive Harlem children discussed in the article, or that it might be a promotion still from Guinea Pig Kids.

U.S. orphans living in such cramped, squalid conditions? Say it ain't so.

It ain't. The photo, credited to Klaas Lingbeek-van Kranen, was taken in an Addis Abba, Ethiopia, orphanage run by nuns, according to the stock photography house iStockphoto, where it can be purchased.

Nature Medicine Editor Juan Carlos López says he approved the picture prior to publication but was not aware that it was taken at an Ethiopian orphanage until I contacted him. He says the journal's production editors routinely identify images for it and that this particular image was not queried by the publication's fact-checker. Although the image's vague caption does not state that the scene was captured in Harlem, Lopez concedes the unnecessary confusion it may have caused.

Nature Medicine's goof—or one like it—can happen at any publication that uses stock images to illustrate, not necessarily document, articles. Slate, for example, uses lots of stock images, but its art and editorial departments avoid images that will be interpreted as literal expressions of stories unless, of course, they're supposed to be read literally. A photo of Mitt Romney illustrating a Slate story about his "Mormon" speech should come from the speech. A photo of Romney illustrating a story about his position in the horse race need  not be specific, although it should be of recent vintage.

Picking the "wrong" photo for a magazine story was a lot harder back in the old days, before the Web-based photo agencies got going. The job of picking images usually went to experienced photo editors, people who possessed an encyclopedic knowledge of photography and photographers. They had to assign photos or know how to find the picture they needed in the fat books of stock pix they kept on their shelves.

Nowadays, anybody with a browser and an account can select and purchase images from Getty, Corbis, Newscom, iStockphoto (where this one came from), or other agencies. Unless that person is trained or closely supervised, goofs like Nature Medicine's are bound to happen.

Don't get me wrong. It's all to the good that today's publications have instantaneous access to millions of photos. And, generally speaking, it's a good thing that the Web reduces the amount of human skill required to find quality art.

What's lost in the new order is harder to quantify. Although the visual catalog has grown larger thanks to the Web, the images selected by publications often seem generic. The Web's bounty in untrained hands can conjure sameness as easily as variety.