This document discusses illustrations, photographs, and drawings. It provides information on what each of these visual elements are, including that illustrations are created by artists to visualize subjects, photographs are images captured with a camera, and drawings involve using tools to mark a surface. The document also discusses how these visual elements can help readers understand ideas and concepts in texts by providing depictions or additional context that words alone may not provide. It notes that illustrations and drawings are sometimes used when photographs are not available or to simplify complex topics.