This practical and informative book gives a detailed analysis of how pictures can be used in computer systems to convey information to users. A major concern is to highlight the relationship between pictures and linguistic representations of information. The authors define a new classification for pictures that focuses on the tasks users carry out with the help of images on computer screens, and present a model for analyzing and influencing the flow of information via pictures. Numerous examples are given to illustrate the ideas presented. For specialists in computer science, the book bridges the gap between computer graphics and human-computer interaction, while for general readers, it offers a wealth of insights and practical advice on how to use pictures as a medium of communication.