Illustrative material is any type of visual representation used to help explain or illustrate a concept. This can include PHOTOS and ART, which are two of the most common forms of illustrative material. PHOTOS are usually taken with a camera and can be digital or printed. ART is a form of visual expression that can be created using a variety of mediums, such as paint, pencil, charcoal, or clay. Both PHOTOS and ART can be used to help explain or illustrate a concept in a way that words alone cannot.