Every Frame Has a Silver Lining

Published in the collection The Lives of Harry Lime - novelization of episode 13 of the radio program of the same name as the collection.
Though Harry Lime has claimed strongly that he does not deal in drugs, in this adventure he is in Tehran and comes into contact with a man named Pappas who has $50k in opium which Lime gets his hands on. Putting it into the frame of a picture, Lime convinces an American family to take it back to the States.