Since Bing and the Google started filtering "duplicate" images from the Image Search, there has been a steady rumor that Google will start penalizing similar images like it is penalizing similar text content now (well, not "penalizing" but let's say "filtering out"); both in- and cross-domain.
That would presumably mean, everyone who uses images from iStock or similar sites are going to be penalized...
Jill was pretty much clear when she was asked that question in comments:
Paul Schlegel said: I am now hearing rumors that Google has started penalizing sites with duplicate images, such as the one you've used in this post. Jill Whalen said: @Paul, that sounds kinda silly to me therefore I wouldn't believe it. Paul Schlegel said: OK. It was from a post by Roy Reyer - I don't know anything about him other than he did some trainings with Jerry West. I could be misinterpreting the post, too - or like you said, it could be nonsense. Let me know if you want a link to his article. Jill Whalen said: Found the article. He seems to be talking about product images on eCommerce sites. But I still think it's total BS.
But I heard very experienced SEO say "when it comes to Google, I will believe anything now".
Now, I have my own opinion, but I would love to hear yours!