I didn't post the entire photo; I posted the link to it.
What I did use amounted to 10.25% of the original photo (basically transforming it) which combined with the fact that it was posted purely for purposes of discussion from which I will in no way profit made it acceptable under the fair use exception to US copyright laws.
But of course that is just my opinion, and I'm certainly no legal expert.
I see that the photo has also been removed from the blog where I originally found it. As all of this happened within an hour of my post, I assume that the copyright holder is a reader of this board. I realize that we have a certain unwritten code here, so my apologies to the owner for not seeking permission.