NEW YORK (AP).- A 12-year dispute that illustrated the difficulty of proving art was stolen by Nazis in World War II ended Tuesday with an agreement that a 1912 oil painting entitled “Portrait of Wally” will be returned to a Vienna museum and displayed with an acknowledgement that it was stolen from a Jewish art dealer by a Nazi agent. The settlement calls for the Leopold Museum to own the painting by Austrian expressionist Egon Schiele after paying $19 million to the estate of Lea Bondi Jaray and allowing it to be displayed for three weeks at the Museum of Jewish Heritage in lower Manhattan. The painting has been the subject of court proceedings in New York City since it was lent 12 years ago to the Museum of Modern Art in New York by the Leopold Museum. At least three times, a judge had ordered it returned to Austria without acknowledgement it had been stolen. U.S. Attorney Preet Bharara said in a statement that the set