The new info was based upon his autopsy, which measured him at 5’2"- okay back then not that short, like two inches shorter than average.
But they have said they measured him in old Royal French feet and inches, not Imperial British.
But why would they do so? His autopsy was done by four British doctors and one Corsican. None were french- why would they use a rather obsolete french measurement?
IIRC Napoleon was the boogeyman of that era. They wanted to slander him any way they could. His height was one way they they did that. Never mind the truth of it. Slander was the point.
I can see that, and certainly, even if he was 5’2" he wasnt exceptionally short in those days (the French army required a man to be at least 4’11"). But generally a cartoon is based on something- then blown out of proportion.
Then there was his nickname that his own men gave him.
Another reason for the rumors could be that he was often depicted in painting with his imperial guard, who were chosen for their physique and so were far taller than typical men of the time (and wore bearskin hats to accentuate their height)
Per Wikipedia, the French pied (foot) was equivalent to 324.8 mm in 1799, when it was abolished and replaced by the mètre.
Napoléon himself reintroduced a slightly different pied for commerce, at 333.3 mm, in 1812.
In 1840, Louis-Philippe eliminated the pied and made the mètre mandatory again.
The English foot was, apparently, already around 304.8 mm in that period.
So, yeah, there can be some uncertainty on the type of foot used in the 1821 autopsy of a Corsican-born former French emperor, by one Corsican and four English doctors.
I also wonder about it this way: Someone who is not “short” but fairly average could have height insecurities and be comparatively short/not tall in certain contexts. For example, a 5’9-5’10 man now would be fairly average. He would be short for a CEO/President/military leader (maybe?)/athlete in most sports any level past JV/little league. A lot of men think they have to be “at least 6 feet” (if not taller) to compete in dating/the workplace/etc. Some guys use lifts, even heightening surgery. So I think a 5’5 guy in the age of 5’5 men might still be insecure he’s not “tall” and he might be diminutive for a leadership position.
Also the people who started and spread this rumor were not poor peasants and factory workers who were raised in the edge of malnutrition. They were the political and military elites who would actually encounter the emperor of France on a regular basis (or would hang out and gossip over a glass of wine with people who did). So their average height was likely close to the modern average, as they had good diets, so them he would be short.