Custom App Icons via download images/packs etc.

Something like the background selection, where you can select single (or more) images or folders. I think, it doesn't really matter if its automatic or a manually assignment of the images to the app. But if its automatic, the name of the images could correspond to the app, it will be assigned to.

This could be a very requested feature. I didn't really find on here but on reddit are a lot question on how to change to custom app icons.