I found a collection on the Library of Congress website that has pictures of U.S. Presidents and First Ladies. The collection was called, By Popular Demand: Portraits of Presidents and First ladies. The following website contains photographs of Presidents and first ladies past and present. The pictures of both the Presidents and the first ladies date back to 1789. There are 156 photographs in this collection. According to the website there are thirty-six wives in this collection and the collection also includes pictures of forty-one presidents. There are not pictures of all the first ladies and Presidents. The home page for this collection is:
http://memory.loc.gov/ammem/odmdhtml/preshome.html
Here is a picture of Mrs. John F. Kennedy. This is a picture by, Mark Shaw and it was created in 1961.