Remote media download just works (tm) too, very easy to get the remote homeserver base url properly with https://www.npmjs.com/package/@modular-matrix/autodiscover-client-configuration
and initial commit published!
https://git.pixie.town/f0x/synapse-media-proxy
oh yeah and also verifying the symbols in the requested mxc for 'security reasons' lol
oh and removing that lol