I wonder about info leakage with that one, the poster uses that exact photo as their avatar so if they've mentioned Alki Beach before then reverse image searching might pick it up from context. Ideally you'd want to test it with a photo that's never been posted online.
I’m also completely ignoring it inferred location from the pride flag and corgi which have heavy Seattle vibes :)
Don't upload your private photos anywhere.
It isn’t magic. I think there we’ll often be surprised by the “hits,” but it’ll also get a lot of “misses.” A random photo in your back yard that doesn’t show the horizon will probably be a miss, right?
Meanwhile, lots of photos already include GPS coordinates… data you can strip out, but which is enabled by default for millions of people. Privacy, eh, never knew it I guess.