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.