According to Don Norman, in his book titled the “Design of Everyday Things”, {1} a System Image can be thought of as the bridge of communication between an engineer, and a user. Because the engineers can not directly speak to a user, they have to hope that the system image, often a manual or picture, can speak well enough on their part to the user to convey the correct message.
1) Norman, Donald A. "The Complexity of Modern Devices." The Design of Everyday Things. New York: Basic, 2002. 4-8. Print.
1) Norman, Donald A. "The Complexity of Modern Devices." The Design of Everyday Things. New York: Basic, 2002. 4-8. Print.