Sometimes when SEOs run tests, we find hacks and workarounds for ways to get things done. I’ve recently been running some tests about rel=author, to try to get it to show for my site and others.
I now have conclusive proof that rel=author is not algorithmic. Rather, it is manual by site AND author. And I bet that the authority of the site has something to do with whether or not it shows as well. So we have a combination of who the author is as well as the specific site. If your photo shows for one site, it will not necessarily show for another.
Allow me to demonstrate.