Remember that all relays are web servers.  That means they all have in built ability to store media, which can be turned on or off.  Never push media itself to the relay.  Relays are for transmitting notes, and other stuf, from one user to another.  But all relays, inherit the ability to store media, from the fact that relays are already web servers. 

 Are you willing to do an introductory explainer on some good practice options?