Nobody can steal copyright, they can steal the image (which is not the case here) or the original copyright holder can assign rights to others, which is the case here. If you don't agree with an end user license and their draconian copyright sharing policies then don't tick the box to signup for an account.
Further, once you have ticked the box and got an account there is usually a clause in there that states you agree to any changes unless you opt out, that is, if you don't monitor what changes they make to the agreement and do nothing then you are considered to have agreed with the changes.
So, pay attention to the agreements you make and any emailed changes to the end user license. Don't post anything unless you are happy to give it away anyway, these big corporations might be trying to make money off your images legally but plenty of people are happy to just copy and paste, steal, your image if it is what they want. Never, ever, post a high res image anywhere unless you really don't care about it, plenty of customers will be happy with even low res small prints they can take off proofing web pages without paying.
Talking of high res images, for this forum I did post three comparison images at full res on a hosting site, despite the fact that probably only 100 or so people read the thread, the links were not high profile and few would have found the image interesting they have subsequently been viewed over 5,000 times in two weeks. That hosting site has tagged them, I didn't, and the images are now searchable, and they are obviously coming up in searches.
Which hosting company? I'll want to avoid it if I can...
Thanks. Interesting, never heard of them.
Is anyone else totally hating the bottom footer (e.g. About, FAQ, Help, Contact Us, etc) that keeps disappearing? It's freaking annoying! I want to click on those, but they are never visible on the screen! WTF! Facebook is another big offender when it comes to that and the timeline. Grrrr...
Oh, and found another opinion on the updated Instagram policy. Looks like it's more a clarification of language that already sorta gave them those rights anyway.