Reminds me of a line from a song I like:
"Though we might have precious little, it's still precious".
As far as I know, the photos (film and otherwise) I post on the web are worth precisely nothing until, of course, the point where someone decides that they want to use them to promote their goods and/or services; at which point they acquire a value, however nominal.
That said, they are my photos / images and no (anti)social website should be able to sneak me out of either copyright or claim that they can use them, at will, for their profit (financial or otherwise) without asking me for (and receiving) my (or my estate's) explicit permission beforehand. It's just simple, good manners and honourable business practice.
There's nothing I have posted anywhere on the web that I wouldn't delete in an instant if I thought some entity intended to take unreasonable liberties with it or fail to protect it as best they could against theft or use against my will or knowledge.
I know most of us pay precisely zero to post most of our stuff but that's up to the website. If they don't earn enough from advertising to cover expenses and they're not able to stand the cost themselves, then charge a fee. I'm sure many (if not most or all) would pay something reasonable if web hosts asked and could prove their value.
We live in dangerous times, folks, when our governments allow anyone to take what is ours, conceptually, intellectually or even physically, from under our noses by warrant of some weasel words imposed upon us without the necessity for us to agree or the ability to opt out.