The photo is real, but it's not the Buffalo Bill Dam.
E-mails and Facebook wall posts claim that the photo on the left pictures sheep climbing the dam near Cody, Wyo.
The Buffalo Bill Dam has a smooth concrete face with no stones, whereas the dam in that photo has large stones visible in the face. Also, the canyon walls surrounding Cody's dam are much different that the grassy hills shown in that photo. A side-by-side comparison (to the left) proves they're not the same dam.