A previously unseen press photo of a teenage Princess Diana that a London tabloid decided not to publish has sold for US$18,306. The picture shows Diana, possibly in a ski chalet, smiling at the camera as she lies comfortably in the lap of a young man reading a book. But the most intriguing aspect are the words "not to be published" scrawled across the photo. On the back, the picture is dated February 26, 1981 - two days after the engagement of Prince Charles and the then Diana Spencer was announced. The American auctioneers said the photo came from the private Caren Archive, which acquired it when it bought out the photo library of Britain's Daily Mirror newspaper seven years ago. The identity of the buyer was not revealed. The young man in the photo is said to be Adam Russell, the great-grandson of former British prime minister Stanley Baldwin. Diana died in a Paris car crash in August 1997, a year after her divorce from Charles. She was 36.