Please do share where I can reliably store my backups for free!

This does still happen. Microsoft may nuke a git repo and someone has to figure out who has the latest version of the entire repo with all the latest commits of every branch.

The vast majority of people aren't privileged enough to have anyone mirror their data.

But how do I get everyone to mirror my gigabytes of encrypted photo backups?

Title it "(current star name) Leaked Nudes.zip" and seed a torrent? Every few years, change the title to keep it current.

They don't allow uploading large binary blobs either, though, and steganographically storing gigabytes of data with probably terabytes of overhead sounds like a quick way to get banned.

dump it on Wikipedia. afik wiki never removes anything. it just gets buried in an edit history . or Wikimedia image files

That obviously can't be true, or spammers would be all over it, using Wikimedia as a free image host.

There was a story making rounds a few years back that Wikipedia was being used as a file / media sharing platform, particularly in countries with limited other options for such services.

I can't find a link currently, though I'm pretty sure I'm not hallucinating this.

Are you thinking of this by any chance? https://phabricator.wikimedia.org/T273741

That wasn’t really somebody using Wikipedia as a file storage, but rather as a web connectivity test.

Nope, though that's interesting and somewhat expected.

I remember when web-connectivity test was spelled "Slashdot".