This is the home of the UWP Tile Generator which can provide the tiles you need to submit your application to the store from a single high resolution source file or SVG.
The project is a Visual Studio extension which can download from here: https://visualstudiogallery.msdn.microsoft.com/09611e90-f3e8-44b7-9c83-18dba8275bb2
The UWP Tile Generator was designed to help developers adhere to the Windows Design Guidelines on tiles: https://msdn.microsoft.com/windows/uwp/controls-and-patterns/tiles-and-notifications-app-assets