Okay, but, it really looks to me like his golf shoes in the previous picture -- like this is the bottom of the shoe of someone walking away. Sorry to be perverse.

I agree and see the similarity. But it doesn't work anatomically. So I switched from assuming shoe and tried to figure out what else it could be. Simply not enough pixels in the pic to be sure. If someone can get their hands on the RAW pic we can do more with it to explore.