Books
Rousseau shows how people learn by presenting imagery of books; in particular, he shows what it looks like for a child to be studious at different developmental stages.
The Outdoors
Rousseau additionally depicts the types of education through pastoral imagery and that of a city. Emile learns through exposure to townspeople and also through seeing animals in their natural element.
Family
The choice of imagery to show how family operates is striking, and Rousseau is able to use descriptive literary elements in his exposition of the way role models, particularly parents, can affect a child's surroundings and cause him or her to learn fully.
The Reader
At various parts in Emile, or On Education, Rousseau addresses the reader directly. His use of imagery to do so helps capture the reader's attention in a more visceral sense than he would acquire if he stuck to a strictly didactic tone.