Interesting... and odd. I mean it doesn't show up if I just try to "View Info" using Firefox, but if I literally download the image and save it to my desktop and re-open it in Photoshop, even the thumbnail was copyrighted. Example (which is currently set to a CC license so you can download the images, but the copyright should still be embedded).

I'm at work on a PC, so I'll have to try again from my Mac at home, but if I find one that seems to work I will let you know. :)