Many people just don't understand about intellectual property rights and that picture theft is wrong. As an example, I work at Trade Me (NZ's version of Ebay). Sometimes we'll get contacted by the rights holders at various companies: OPI, Leg Avenue etc, who will let us know one of their images is being used on an auction without their permission. We contact the person selling the item and let them know we have removed the photo and that they'll need to take their own photo of the item because they don't own the rights to the one used. Seems simple enough, and most people will say "oh shoot, I'm sorry, I didn't realise that was a problem" and it doesn't happen again.
In contrast, I had a really long conversation with a guy who simply could not comprehend what I was telling him. He would keep saying, "X person is using this photo on their auction, can I use that?" No - not without their permission, that is still image stealing. "What if I just crop the person's head out?" No!! That's still stealing! Just take your own damn pictures!!
I feel with so much content being freely available on the internet these days that there is less understanding that the same rules still apply. I watermark my own images right across the middle and someone still had the audacity to steal one and use it on their auction for a pigment sample they purchased from me and were re-selling (for three times the price, and they tried to sell it back to me, but that's another story...)