Nope. Haven't noticed.
Plagiarism is a pretty poor practice, if that's in fact what has occurred?
It's also a fairly serious claim to make if you're unsure.
Would be very disappointing if it's true, and count heavily against the individual carrying it out.
I reckon the best policy is to simply question the person at the time of posting the image.
I know that's potentially embarrassing, but if you put an image out there on a website that isn't your own then it's already in the public domain
