His work can be found in museum
collections worldwide, including the Art Institute of Chicago; Maison Européenne de la Photographie, Paris; The Metropolitan Museum of Art, New York; The Museum of Modern Art, New York; and the National Gallery of Art, Washington, D.C. Penn has published
multiple books of photographs: Moments Preserved (1960); Inventive Paris Clothes (1977); Issey Miyake (1988); Passage (1991); Still Life (2001); Photographs of Dahomey (2004); among others, as well as two books of drawings.