Here's a picture of Mark Zuckerberg that was posted to the image-sharing site Imgur. The picture was accidentally uploaded publicly to Facebook by Facebook Director of Engineering Andrew Bosworth and deleted "seconds later," according to a screenshot posted by TMZ. Yes, you can see his nipples.

But what, exactly is going on here, in this epic shirtless billionaire bro-down? Are they about to jump in a pool of money? Now that Zuckerberg only eats what he kills with his bare hands, perhaps he's stripped down to butcher a pig or something.

Update: A tipster tells us this was taken during the wedding of Facebook product manager Justin Shaffer and Annabel Teal. According to Teal's Facebook page the wedding took place on August 4th at Lightning Tree Farm in upstate New York.

Our tipster also sent us this delightful photo, which features Facebook product manager Sam Lessin growling at the camera, and Shaffer himself with his back to the camera. Seems like it was quite a party! But does anyone know what they're doing with their shirts off? Let me know.