Can't say enough good things about flickr. Those people nailed it in 2004 (I've been a paying subscriber since their first year) and everyone else has been making bad copies ever since. Tagging, friends (pretty much inventing social media without any of the diabolical dark patterns), full-resolution archival storage, a solid API, all over two decades ago. I'm frankly embarrassed for things like Instagram, it's like they're not even trying.