I obviously can't speak on behalf of PF, but I'm sure they weren't intentionally meaning to cause you upset. They obviously wanted to promote the feature, and maybe didn't have their own pictures at the time of going to press. I'm also sure that if they knew you were the owner they would've sought your permission first/credited the photo to you.

They're a good bunch of guys, and I'm sure they'll try to make amends.

What are you after as a result of this, would a credit in a subsequent issue be satisfactory?