File:John Maurice Clark.jpg

Summary
The image comes from "The Warren J. Samuels Portrait Collection at Duke University, found online at  The Samuels collection generously offers and encourages the "free use of its portraits of economists in Web documents, and for other educational purposes".

Fair use for John Maurice Clark
The image linked here is claimed to be used under fair use as:
 * It is an historically significant photo of a famous individual;
 * It is of much lower resolution than the original (copies made from it will be of very inferior quality)
 * The photo is only being used for informational purposes.
 * Its inclusion in the article identifies the subject of this article and adds significantly to its educational value.