Why just guess though?
If the Law governing IP in Luxembourg only protected exact copies, the reasoning wouldn't have had to have been about the pose, it would have been that the painting wasn't and exactly copy of the photograph.
If the Law governing IP in Luxembourg only protected exact copies, the reasoning wouldn't have had to have been about the pose, it would have been that the painting wasn't and exactly copy of the photograph.
However either way, I see no reason to think about copyright in such a limited way. I don't think many people believe that copyright is only enforceable if two works are exactly the same. Rather I think they're simply discussing how inspiration and imitation is very common in art.