Citing images can be tricky. To cite an image/reproduction of a work of visual art, follow this format:
For an image from an electronic source:
APA
Author (Role of Author). (Year image was created). Title of work. [Type of Work]. Retrieved from URL
Smith, Z. (Painter). (2008). One hundred more years [Painting]. Retrieved from <http://www.artstor.org>
Sayer, L. (Photographer). (2007). Nurse log. [Digital Image]. Retrieved from http://www.flickr.com/photos/riss/368673880
Chicago
Artist's name, Title of Work. Date. Materials, Dimentions of work. Museum name and location. Available from database. URL. Date of access.
Fig 1. Caravaggio, The Denial of Saint Peter. Early 15th Century. Oil on Canvas, 94 x 125.4 cm. The Metropolitan Museum of Art, New York. Avalable from: ARTstor, http;//www.artstor.org (accessed 14 July, 2015).