Two distinct approaches to the analysis of illustrations are described. Functional analysis, which is based on the view that what an illustration looks like is less important that what it is meant to do in a given text, is seen as a more useful approach than morphological analysis, which is concerned with what illustrations look like. Three categories of functions of illustrations in an instructional situation are discussed: an attentional role, an explicative role, and a retentional role. These roles are compared with categories proposed by Levin, i.e., motivational, organizational, interpretational, representational, and transformational, and relationships between the two systems are shown. Ten references are listed. (CHC)