Xamarin.iOS Using iOS Asset Catalogs to Manage Images
Remarks
Asset catalogs are way to manage multiple resolutions of iOS image assets. In order to display optimal images, iOS uses 1x, 2x, and 3x versions of each image according to the device's screen density. The 1x version is only for very old, non-retina devices so it isn't necessary for apps only supporting iOS 9.
Asset catalogs will help support app thinning and slicing, optimizing the resources users have to download to install an app from the App Store.
