It's https://lumina.rocks/. The whole time Olas was down, my feed was full of people complaining that they can't post anymore pictures, but you can post kind 20 image notes from lumina, nostr.build, Amethyst, and Jumble, just to name a few, and Derek even jumped in with an emergency replacement, and they were all working fine.

But, when Olas went down, the picture feeds stalled out, as everyone stopped posting, all at once. It's like when Primal goes down or etc. Nobody thinks, "Oh, I'll just use a different one...." And lots of the people who "take a break, waiting for Nostr to get fixed" don't return. Lose users, everytime, due to this extreme centralization.

We're too much like the Matrix protocol, where you can use any interoperable client, so long as it's Element.