I'm not so sure it would qualify for any kind of copyright violation. Take Google, for example.

If you click on images and type in "cats" or "kittens" you get hundreds of thousands of images of kitties.

If you were to "take" one of those images and put it on another web site (as long as you're not selling it to make a profit), I don't know that there's anything wrong with that.

I would be flattered if they used a photo of one of my kitties, but I think I would like permission first.