That particlar image is not GFDL, It is (I believe) this image: http://commons.wikimedia.org/wiki/File:Hpim3526.jpg
The license says "The copyright holder of this file allows anyone to use it for any purpose, provided that credit is given and copyright is attributed..", so it is certainly a violation of Marko Petrovic's copyright.
I don't think that the violation is malicious, just them being slighty lazy and assuming the copyright lies with "wikipedia", they are not trying to claim it as their own. Therefore the first thing would probably be to write them an email pointing out their error and asking them to amend the page.
James
