Over the past couple of years, the trade publications have been filled with stories announcing the arrival of a new era in journalism -- one in which independent media thrive, news agendas are formed from the grass roots up, and everyone is a journalist.

The mainstream news media, we are told, are being usurped by a new cohort of citizen-journalists who are applying new technology and a disparate set of ethical standards to outmaneuver their bigger competitors.

These assessments are probably exaggerated, but there is no denying that things have changed. Not only is there an increasing amount of news available from bloggers and other micro-media, but the relentless cost-cutting by mainstream organizations has led them to rely increasingly on syndicates, stringers and part-timers.

Even average citizens, armed with camera phones and pocket-sized camcorders, are making regular contributions in the world's elite media.

So how should news organizations evaluate the integrity of photos and videos that come from third parties? And what risks do they run by putting their trust in people who have no vested interest in the organization's success or its public reputation?

These might not seem like urgent questions for mainstream media organizations, which, after all, have been employing stringers and purchasing syndicated work for decades.

But things are different today, in part because of the sheer volume of content being supplied by third parties, and in part because some of that content is coming from people with no journalism training, no fidelity to the profession, and no fear of any kind of professional censure.

Most mainstream news organizations have taken seriously the need to establish written codes of ethics for their journalism employees. These codes help give organizations an ethical identity, they help ensure consistency of practice, and they give the audience some sense of what to expect.

All of these things are undermined, however, when organizations use third-party content without subjecting it to the same standards as their staff-produced content.

To avoid these kinds of problems, news organizations should assiduously filter outside contributions by asking several key questions.

IS THE PHOTO OR VIDEO WHAT IT PURPORTS TO BE?

In the weeks following Hurricane Katrina, dramatic photos were circulated on the Internet showing a series of beautiful but ominous cloud formations ostensibly created by the leading edge of the hurricane. The photos were actually the work of storm-chasing photographer Mike Hollingshead, who captured the images in the Midwest not the Gulf Coast, but people unknown to Hollingshead discovered the images and passed them off as something else.

We do not know of any mainstream news organization that used these particular photos, but they are the kinds of images that news organizations will increasingly encounter. The hazards of using them without knowing their true origin should be obvious, but in today's competitive news environment, well-meaning editors and producers can still be fooled.

HAS THE PHOTO OR VIDEO BEEN ALTERED?

Today's technology makes photo manipulation so easy that even the top photographers at the best organizations (e.g., former Los Angeles Times photographer Brian Walski) occasionally succumb to the temptations. Those temptations are probably even more keenly felt by freelancers and independent photojournalists who are trying to make names for themselves in the industry.

Detecting these manipulations is extraordinarily difficult even when the photographer is a regular staff member subject to ordinary supervision. When the photographer is a third-party contributor, however, detection is next to impossible.

The risk of being burned by falsified photos is one that all news organizations have to face and one for which there is no foolproof shield. But the risks are substantially multiplied when a news organization routinely uses the work of third-party contributors who are not subject to the same checks and safeguards as regular staff members. At the very least, then, these organizations should be clear with their outside contributors about the kinds of alterations they permit. Even better would be to couple those discussions with a specific provision in their contracts that specifically and clearly outlines the organization's ethical standards and expectations.

WHAT IS THE BROADER CONTEXT OF THE PHOTO OR VIDEO?

Suppose that an amateur photographer captures still photographs of two police officers punching, subduing and handcuffing a particularly rowdy Chicago White Sox fan in the hours after game four of the World Series. Standing alone, the photos might suggest that the fan was unnecessarily beaten and that the police were abusing their authority. But without knowing the full context, it would be hazardous to jump to those conclusions.

Maybe the suspect was saying things to the officers that they reasonably perceived as threats. Maybe the suspect threw a bottle at them before the pictures were snapped. Maybe the suspect is a serial killer who just escaped from jail. We simply do not know.

No editor or producer should publish photos or air video without knowing something about the context in which they were captured. Newsroom leaders need to regularly ask questions about context, even when the truth of the messages conveyed in the photos or video seems self-evident. The need for this kind of scrutiny is especially acute when the photographer is not a regular employee of the news organization. Before using third-party content, editors and producers should make sure that those contributors are available to answer any questions that people in the organization might have. An even better strategy would be to only use the work of credible professionals - staff photographers or established freelancers - who are already attentive to context.

HOW WAS THE PHOTO OR VIDEO ACQUIRED OR CAPTURED?

Users of third-party content are forced to put a lot of trust in people they do not know. If a contributor were to stage a photo, for example, or invade someone's privacy, or break the law, how would anyone in the organization find out? Some of these lapses might be uncovered by questioning contributors about their work and how it was gathered, and that is certainly something editors and producers should do. But the best way for news organizations to minimize these risks is to use less third-party content and to rely on a smaller group of known, credible contributors.

DOES THE CONTRIBUTOR HAVE AN AGENDA?

After it was revealed last year that the Bush administration had been sending out video news releases (VNRs) - promotional pieces packaged as news stories - to media organizations as a way of advancing support for its legislative agenda, alarm bells were sounded among journalists about the increasing risks of outsider influence.

The use of VNRs is not new. But as these public relations tools have grown more sophisticated, and as news organizations have grown hungrier for cheap content, the hazards have multiplied. News organizations cannot maintain their credibility if they allow their news programming to be infected with embedded commercial messages. It is up to editors and producers to make sure that VNRs and all other content supplied by self-interested parties does not find its way into the news hole.

All of the questions listed above need to be regularly and repeatedly asked by news organizations that rely on third-party content. It is reasonable to assume that the cost-cutting in the industry will continue and that news organizations will continue to have an appetite for content produced more cheaply and more abundantly by outside contributors. But it is also reasonable to assume that if news organizations do not aggressively scrutinize this content and do not apply their ethical standards to everything they publish or broadcast, their credibility will continue to sink.