Can't find what you are looking for using the library databases? Try searching reputable art museums' online collections, such as MoMa and The Met! These will provide better, more creditable information and images than Google. No matter what, never cite Google as the source of your image!
Most databases provide a citation for images or articles. However, if you get an image off the web, you'll want to cite it using the Chicago citation style since you are using the image in a Humanities class. You must cite the original location for the photo; never cite Google! Here are some examples:
Last, First M. Photograph Title. Month Date, Year Created. Collection, Museum/Institution, Location. Accessed Month Date, Year. URL.
Cartier-Bresson, Henri. Juvisy, France. 1938. Museum of Modern Art, New York City. www.moma.org.
Caravaggio, The Denial of Saint Peter. Early 15th century. Oil on canvas, 94 x 125.4 cm. The Metropolitan Museum of Art, New York. From: The Metropolitan Museum of Art, http://www.metmuseum.org (accessed September 29, 2009).
Thomas Eakins, William Rudolf O'Donovan. 1981, Black and white photographic print, 6 x 8 cm. Archives of American Art, Smithsonian Institution, Washington, DC. Available from: Flickr Commons, http://www.flickr.com/photos/smithsonian/
2547841439 (accessed September 29, 2009).
Purpose/Point of View