WASHINGTON (Reuters) - A grainy U.S. Air Force photograph that NASA (news - web sites) originally dismissed as being too fuzzy may in fact show the deadly effects of missing tiles on the space shuttle Columbia, the Washington Post reported on Saturday. The picture taken in the last seconds of Columbia's existence shows what may be a vortex of superheated air roiling over the left wing and a section of heat-shield panels missing from the leading edge, the newspaper reported. It quotes an official close to the Columbia Accident Investigation Board, which is charged with finding out why Columbia, NASA'S...