“Hiroshima: Ground Zero 1945” is a new exhibition of once-classified images of atomic destruction at Hiroshima presently on display at New York City’s International Center of Photography. The collection of photographs both repels and fascinates the viewer, with its powerfully ugly portraits of an unpeopled and obliterated city. The photographs were originally part of a governmental analysis of the atomic bomb’s effect on concrete, wood and steel, and this catalog of devastation was meant to be seen only by postwar architects and engineers tasked with erecting the “bombproof” cities of the future.The Hiroshima photos have a strange and contorted history. In the mid-1990s, the owner of a diner in Watertown, Massachusetts, was walking his dog when he spotted a beat-up suitcase sitting in a pile of trash. It turned out that the photographs inside had once belonged to Robert L. Corsbie, an engineer and expert on the effects of the bomb. Just how those photos wound up in his possession remains unclear. Corsbie belonged to a cadre of ordnance experts, engineers, photographers and draftsmen who were sent by President Truman to analyze the nuclear devastation.