( CNN ) -- An intimate black-and-white photograph of Princess Diana as a teenager sold Friday for $ 18,396 , a New Hampshire auction company said . The photograph -- which may never before have been seen by the public , RR Auction says -- offers a glimpse of the future wife of Prince Charles lying down , perhaps on a bed , wearing a light sweater or top . Only her head and arms can be seen . Behind her a young man leans against the wall , reading , his book resting on her shoulder . The future princess looks relaxed , half smiling at the camera . A bottle of whiskey can be seen on the windowsill . Another man is half seen in the foreground , but there is no clue as to who he or Diana 's other companion might be . Large , black wording across the top of the photograph states `` Not to be published , '' and there are two dark lines under the words and above Diana 's head . A lighter circle encompasses the words , Diana and the man reading the book . The only indication of date is a stamp on the back of the print saying 26 February 1981 , two days after the engagement of Diana , then 19 , and Prince Charles was announced by Buckingham Palace . They married in July of that year . The photograph likely was taken a year or two earlier . CNN 's Joseph Netto and Laura Smith-Spark contributed to this report .
An intimate black-and-white photograph of Princess Diana had likely never been public before . `` Not to be published '' is written across the photo . Behind her is a young man resting his book on her shoulder .