@cypnk unsplash.com is a good website with high quality photos under a free license and deviantart.com is a good website for everything creative. None of them require an account.
@cypnk That is unfortunately a thing on most sites, but it's more common on sites like Pinterest where there's a lot of noobs, if I may word it like that. I think it's not so much that they don't care, than them not actually understating why you should not reupload others anywhere at all.
@hund There's also https://www.pexels.com/ Sadly, these are few and far between and they too represent bottlenecks on the open web. A lot of niche photos that originally came from some source on the web eventually ends up on Pinterest and get's locked
I've seen photos from DeviantArt on Pinterest too