While designing icons for your Android or iOS app, it is essential to note that your app may be installed on a variety of devices by different manufacturers. While iOS has only a few smartphone variants, Android devices might offer a range of pixel densities.
The challenge is to make your icons look appealing on all the device types. This can be attained by creating every icon in varying sizes. When the app runs, OS looks into the characteristics of the device screen and accordingly loads the device-specific assets.