This document provides an overview of visual principles for educational technology, including different types of instructional images, the importance of visual literacy, and elements of visual syntax and semantics. It discusses line drawings, illustrated drawings, sequenced drawings, comparative drawings, cartoons, caricatures, maps, posters, charts, flowcharts, and photographs. It also covers framing, angle, lighting, contrast, and other visual elements; defining and enhancing visual literacy; and using images to teach critical thinking skills.