We begin by discussing some of the basic principles of image formation in lenses and mirrors, including reflection in flat mirrors and curved mirrors, use of ray diagrams, real and virtual images, and the different ways in which images can be formed. These basic principles are then applied to gain an understanding of a number of interesting optical phenomena, including mirages, rainbows, and thin-film interference. I conclude the episode with a discussion of optical magnification, and how this is used in telescopes and microscopes.