Option for server owners to allow members to choose from a list of server thumbnails for their own discord apps

Users in a given discord server can choose the appearance of the server thumbnail for their discord submitted by the server owner depending on the groups they are in. A bit similar to the Monzo App where users can change the app icon to a gold icon if they are an investor. The changed appearance will only affect the user and won't change the thumbnail for everyone on a discord server.