Here are two links to explain the ways to cite images in Chicago style
https://sites.google.com/a/colgate.edu/colgatevr/citing-images/citing-images-chicago
http://libguides.csuchico.edu/content.php?pid=214757&sid=1836853
https://sites.google.com/a/colgate.edu/colgatevr/citing-images/citing-images-chicago
http://libguides.csuchico.edu/content.php?pid=214757&sid=1836853