The news organization Reuters reported Monday that it withdrew from its archives all 920 photographs taken by a Lebanese freelance photographer after a review found he had altered two of the images.
Both of the pictures were taken during the current conflict between Israel and the terrorist group Hezbollah.
Reuters said that Global Picture Editor Tom Szlukovenyi called the measure precautionary, but acknowledged that the fact that two of the images by photographer Adnan Hajj had been manipulated undermined trust in his entire body of work.
"There is no graver breach of Reuters standards for our photographers than the deliberate manipulation of an image," Szlukovenyi said in a statement.
"Reuters has zero tolerance for any doctoring of pictures and constantly reminds its photographers, both staff and freelance, of this strict and unalterable policy."
The news and information agency announced the decision in an advisory note to its photo service subscribers. The note also said Reuters had tightened editing procedures for photographs from the conflict and apologized for the case.
Removing the images from the Reuters database excludes them from future sale.
Reuters ended its relationship with Hajj on Sunday after it found that a photograph he had taken of the aftermath of an Israeli air strike on suburban Beirut had been manipulated using Photoshop software to show more and darker smoke rising from buildings.
An immediate enquiry began into Hajj's other work.
Reuters said that the news organization had established that a photograph of an Israeli F-16 fighter over Nabatiyeh, southern Lebanon and dated August 2, had also been doctored to increase the number of flares dropped by the plane from one to three.
"Manipulating photographs in this way is entirely unacceptable and contrary to all the principles consistently held by Reuters throughout its long and distinguished history. It undermines not only our reputation but also the good name of all our photographers," Szlukovenyi said.
"This doesn't mean that every one of his 920 photographs in our database was altered. We know that not to be the case from the majority of images we have looked at so far but we need to act swiftly and in a precautionary manner."
Reuters said that the two altered photographs were among 43 that Hajj filed directly to the Reuters Global Pictures Desk since the start of the conflict on July 12 rather than through an editor in Beirut, as was the case with the great majority of his images.
Filing drills have been tightened in Lebanon and only senior staff will now edit pictures from the Middle East on the Global Pictures Desk, with the final check undertaken by the Editor-in-Charge, Reuters said.
Hajj worked for Reuters as a non-staff contributing photographer from 1993 until 2003 and again since April 2005. Most of his work was in sports photography, much of it outside Lebanon.
Hajj was not in Beirut on Monday and was not responding to calls. He told Reuters on Sunday that the image of the Israeli air strike on Beirut had dust marks which he had wanted to remove.
Questions about the accuracy of the photograph arose after it appeared on news Web sites on Saturday.
Several blogs, including a number which accuse the media of distorted coverage of the Middle East conflict, said the photograph had been doctored.
Reuters contributed to this report.
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