NEW YORK — On buttons, posters and Web sites, the image was everywhere during last year's presidential campaign: a pensive Barack Obama looking upward, as if to the future, splashed in a Warholesque red, white and blue and underlined with the caption HOPE.

Designed by Shepard Fairey, a Los-Angeles based street artist, the image has led to sales of hundreds of thousands of posters and stickers, and has become so much in demand that copies signed by Fairey have sold for thousands of dollars on eBay.

The image, Fairey has acknowledged, is based on an Associated Press photograph, taken in April 2006 by Manny Garcia on assignment for the AP at the National Press Club in Washington.

The AP says it owns the copyright, and wants credit and compensation. Fairey disagrees.

"The Associated Press has determined that the photograph used in the poster is an AP photo and that its use required permission," the AP's director of media relations, Paul Colford, said in a statement.

"AP safeguards its assets and looks at these events on a case-by-case basis. We have reached out to Mr. Fairey's attorney and are in discussions. We hope for an amicable solution."

"We believe fair use protects Shepard's right to do what he did here," says Fairey's attorney, Anthony Falzone, executive director of the Fair Use Project at Stanford University and a lecturer at the Stanford Law School. "It wouldn't be appropriate to comment beyond that at this time because we are in discussions about this with the AP."

Fair use is a legal concept that allows exceptions to copyright law, based on, among other factors, how much of the original is used, what the new work is used for and how the original is affected by the new work.

A longtime rebel with a history of breaking rules, Fairey has said he found the photo using Google Images. He released the image on his Web site shortly after he created it, in early 2008, and made posters for the street.

As it caught on, supporters began downloading the image and distributing it at campaign events, while blogs and other Internet sites picked it up. Fairey has said he did not receive any of the money raised.