I took some pictures at Walmart

Apparently, taking pictures in a walmart is not allowed. After I had been there for a while, taking pictures of the INSANE amount of stuff piled up for the buying masses, I was approached by a manager.

"Who are you with?" he needed to know, as if he thought I was sent by Michael Moore.

"I'm with myself." I told him.

"Why are you taking pictures?"

"Everything is very colorful."

"You're not allowed to take pictures in the store" he fumed.

"Can I take your picture?"

"No"

"Ok"

So I turned to leave.

He followed me out of the store. He watched as I took a picture of the sky. I was wondering if that was illegal too.