Screenshots give your potential app customers a glimpse into how your application looks.
One quick way to create screenshots is simply to take them on your device or simulator with the application running, and then upload those to the App Store or Google Play.
You can add additional aesthetics to your screenshots using a variety of services. There happens to be one that imposes your screenshot within the photo of an iOS device, giving your potential customers a look at how the app appears on a physical device.
To add things such as a device/background to my screenshots, LaunchKit has a great Sketch-to-App-Store plugin (http://sketchtoappstore.com/) that can help make this happen, though the devices available to impose ...
