LONDON, Aug 7 (Reuters) - Reuters withdrew all 920 photographs by a freelance Lebanese photographer from its database on Monday after an urgent review of his work showed he had altered two images from the conflict between Israel and the armed group Hizbollah. Global Picture Editor Tom Szlukovenyi called the measure precautionary but said 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...