What kind of cameras did they use in 16th century France?
Dude, you're too smart and thoughtful for this kind of argument: if the skeleton had been painted rather than photographed would that have transformed it into a legitimate portrait in your estimation? Painted portrait or photographed portrait are irrelevant. What's important is that it "portrays."
Oh, and from your link: "This has proved that the portrait did indeed show the person as they appeared during life."
I almost addressed this in my original post, but figured you wouldn't go for the obvious fallacy: your original statement was that a portrait should portray a "living subject." The mummy portraits were painted after the death of the subject, and therefore portray a deceased subject. If we take your argument regarding the mummy portraits, then a photo of a taxidermied bird could be a portrait because it represents what the bird would have looked like in life. However, my example only addressed your need for a living subject. It would have been more legitimate on your part to argue that a bird skeleton
is not a bird, but that's a different question.
I like picking nits...
Can be a fun, social game since we all have nits. At least that's what I've learned from gorillas and chimps.