PETA has a long history of getting celebrities to go nude for their anti-fur campaign, and Pamela Anderson has a long history of going nude for cameras, so this collaboration was a no-brainer. The animal rights organization hired David LaChapelle to shoot Anderson to recreate the iconic shower death scene (spoilers) in Alfred Hitchcock's 1960 film, Psycho.
Wearing nothing but her birthday suit and holding what appears to be a wet T-shirt, Anderson (an honorary director of PETA) gives her best scream face as she looks at an invisible assailant. The poster features the following message: "Meat and dairy farms drain half the country's water. Making a splash for the environment doesn't mean shorter showers. Try vegan."
The PETA website includes quotes from Anderson and statistics about the amount of water it takes to produce various meats, but the photo is clearly meant to be the focus of the campaign, so we'll keep looking at that.