The odds that Lindholm owns the rights to that portrait are pretty slim, Domi. Far more likely it's in the hands of the artist or the publisher. Furthermore, we found it on several BG2 portrait sites--so "fastidiousness" has not yet seemed to be a problem where BG2 use is concerned. Although it is not the way I normally like to do things, it fit basically all of my requirements for Turnabout, and so I used it with credit given to the artist since we were lucky enough to stumble across that information.
And by your reasoning, we could just as easily discuss why you are not using character themes which don't invoke Star Trek, Fallout, Star Wars, etc. But I would find that boring, so let's not.