Experts Say Qaeda Image Unlikely to Be Real Warning of Attack After skyline images of New York bearing a threatening message about the return of Al Qaeda drew police and media attention, terrorism experts on Tuesday cast strong doubts on their credibility. The image - a vista of Midtown Manhattan at sunset digitally overlaid with a city street and emblazoned with the words "Al Qaeda Coming Soon Again in New York" - appeared on the cover of The Daily News on Tuesday and was splashed across Web sites and television broadcasts. "It's something we're looking into," Paul Browne, a spokesman for the New York Police Department, told The Daily News. We're trying to determine the origins of it. We take all things like this seriously. A spokesman for the Federal Bureau of Investigation told NBC News New York that the bureau's "Joint Terrorism Task Force is aware of the posting and investigating its authenticity and origin." Mr. Browne, in his comments on Monday, said that the police believed the images were not posted by an American. "We're leaning toward an Egyptian, using Arabic, to create communications on this site," he said. According to The Daily News, Mr. Browne identified the site as gulfup.com. But that site appears to be simply used for uploading and managing media files. Experts who monitor jihadi postings online said the images instead originated on the Arabic-language version of a known jihadi forum, Ansar Al-Mujahideen. The original post on the Arabic forum includes three versions of the same image with the text arranged in different configurations and with slight variations in the font. The appearance of the text and the skyline in the deep colors of sunset appear to be an effort to mimic the style of a movie poster. At the bottom of that post is the Web address of the image before the text was added. It points to a gulfup.com domain. The post appeared there around midnight on Monday, Aaron Y. Zelin, the editor of the blog Jihadology and a researcher in the department of politics at Brandeis University, said in an e-mail. He said it "appears dubious" that the post was an actual threat. "The pictures were posted in "Department of Audio & Visual" / "Images & Design" as a note on how to Photoshop," Mr. Zelin said. "It was a lesson, not threat," he added. Indeed, the Arabic text at the top of the post also appeared to confirm that interpretation. It described how the images were put together, undercutting the notion that they were meant to signal any new plans for an attack: Peace and mercy of Allah This is a humble attempt I have integrated two pictures of the city and the streets via Photoshop and the rest by Cinema. Do not forget to pray for us. J. M. Berger, a journalist and terrorism researcher, wrote on his site Intelwire that the likelihood of an impending attack being announced this way is remote. He described reports in the New York press as "hyperventilation" and said that the images, while obviously upsetting for many New Yorkers, lacked credibility. Although a lone jihadist or Al Qaeda proper could certainly choose to advertise their intentions in this manner, it is unprecedented for the terrorist organization or any of its online adherents to make so specific a threat. I recently asked a number of intelligence analysts working the forums whether any of the hundreds of threats and wishful plots they had tracked on jihadist forums had ever been realized in an actual terrorist attack. The answer was stark. No plot ever begun on the forums had ever culminated in a successful attack, and only one person was willing to cite one plot that became operational (unsuccessfully). Mr. Berger pointed to the now-defunct Qaeda magazine Inspire, which had occasionally included images of American sites, implicitly as targets. No attacks followed, he wrote. Both he and Mr. Zelin observed that in recent weeks several major jihadist Web sites have gone silent. The Washington Post reported on Monday that two of the main Qaeda forums went down more than a week ago and have yet to return, in what appeared to be a cyberattack. If so, the paper reported, no group has claimed responsibility. Brian Fishman, a counterterrorism expert at the New America Foundation, cautioned against making too much of the law enforcement comments. "New York City undoubtedly remains in Al Qaeda's cross hairs, so it is entirely responsible for the F.B.I. and N.Y.P.D. to investigate this graphic thoroughly," he said in an e-mail. But it is critical that New Yorkers and Americans not succumb to excessive fear over these kinds of incidents. He said that while Al Qaeda's central leadership has pointed toward potential targets with graphics in the past, "for every claim by Al Qaeda or its supporters that an attack is coming, there are 10 that are all bluster." The Daily News appeared to agree with that assessment, publishing an opinion piece by a terrorism expert that doubted the premise of its cover story.