I had not seen that picture of the band before either. 

Something about Idlewild South and Black Hearted Woman on the first album you may not know. The credits on Idlewild South do not provide who is singing the harmony vocals on Revival. Beginning in 1970 I was curious to find how who is singing that "People can you feel it, love is everywhere" and how many of them. Many years ago I had a chance to get near the bus and Dickey was there so I asked him. He wrote the song and I knew his electric guitar was on it. And he answered me. " I know it doesn't sound like it but that is everybody in the band". I was surprised as it actually doesn't sound like six people to me so I said " You mean even Butch and Jaimoe?" And he said " Yes all of us. I remember when we added that and we were all gathered around a mic and singing and clapping our hands together and laughing". 

Several years later I had the chance to mention that to Butch Trucks and he said they all did that on the first album too. On the chant on Black Hearted Woman. But they kept breaking up and almost gave up. They finally got one without anyone laughing except Berry Oakley laughs at the end of it and the producer didn't cut it out. Oakley is laughing on the track. 

Me neither...very cool pic!!!