They don't have to "resell" the photos "as their own". It's the data you hand over to them, including the data in your pictures, which is theirs. I'm sure if Facebook decided to sell a book with one of your pictures on the cover, or if they put your personal photo on a mug and those mugs were then being sold at walmart their terms of service and privacy policies would allow for that, but that doesn't mean that there wouldn't be lawsuits and bad press as a result, which makes those kinds of scenarios unlikely.
More likely they'd sell your photos to third parties who wouldn't make products out of them. Those third parties would just extract as much information as they could out of them and then use that data.
You would never see it happening so you'd never know who to be angry at or when to be upset by it. That data would later be used to manipulate you, take more of your money, assign you into specific categories/castes, etc. but even if you were aware those things happened, you'd never be aware that facebook or your photo was a factor. Facebook gets an extra income stream and you're totally unaware.