For research, images need context and information about their creation to reuse them ethically. Where you locate images can help you with both. Here are a few places to try.
To access their online catalog collections: Click here
The Crystal Bridges Museum of Art Library and the University of Arkansas Libraries share a library catalog--the computer system that searches their collections. You can search their holdings at the link below, and limit to either location.
To access their online catalog collections: Click here