The best explanation I've found for citing images found in books and databases comes from NoodleTools.
You can also create citations using EasyBib. You will be able to choose the material type you wish to cite (painting, photograph, comic, map, brochure,etc.). The Web form will allow you to specify whether you found the image in a book or a database. There is also an option for citing a "Digital Image" that will be useful when you're citing images from online museum exhibits.