[bryan_w]

Consider the following:

You encrypt and upload the media to the storage server.

You share the download URL and key with person #1

Now how long would it take to forward that same message with the url and key to person #2...n?

[prmoustache]

Are you saying they would be using symmetric encryption?

[bryan_w]

Not necessarily, sender generates a private key for the piece of media, and shares the public key for that media item along with the download location to person 1&2 over their encrypted chat channels.