Smart data for apps and analytics. Icon Design Guidelines. An icon is a graphic that takes up a small portion of screen real estate and provides a quick, intuitive representation of an action, a status, or an app. When you design icons for your app, it's important to keep in mind that your app may be installed on a variety of devices that offer a range of pixel densities, as mentioned in Devices and Displays. But you can make your icons look great on all devices by providing each icon in multiple sizes. Factual Home - Factual.