And kieran has a good point: if they wanted to share the link they could just save it and upload it to a public link. Just a few more steps, removing the shared secret from the fallback link would just make a bad UX for little gain.

Maybe nip94 encrypted images (pay per upload/download via specialized relays that want to do this. It’s not free to store and transmit images anyway so users should pay the cost with a single tap like a zap. Anyone could pay the fee and download the data but only correct nsec could decrypt?

It seems to me that nostr is an awesome social media protocol but just not really meant for DMs at all. The current solution seems a little clunky and not scalable to a good messaging experience. What if nostr added some support for people including their matrix usernames and then nostr clients could work to incorporate a full matrix messaging experience in addition to the social media side of things that already works so well. A client like this would have a fantastic social media, messaging, group chat, video calling, and payment (via lightning) experience. It’s like a decentralized super app lol.