An image on a computer screen is made up of a series of dots. The more dots, the more detailed the image. In the same way, insects have compound eyes with many lenses, each producing a "dot" of image. The more lenses, the more detailed the image will be. Dragonflies have as many as 30,000 lenses in each of their eyes, and are very good at seeing movement up to 50 ft (15 m) away while flying.