Images resources such as, but not limited to, image repositories and encyclopedias, provide visual examples for your artist or even help you choose an image to research. Researchers use them when they need:
Box titles: capitalize first letter in key words
Encyclopedia entries and images for art. Includes Grove Art Online, the Encyclopedia of Aesthetics, The Oxford Companion to Western Art, and The Concise Oxford Dictionary of Art Terms. Coverage: varies.
If you have a digital image of the item you are trying to research, use it in a reverse image tool to find similar images on the Internet.