Isn't the death mask unreliable?
There are several websites suggesting that the death mask is distorted due to Joseph's injuries or decomposition. Generally, they question the mask because it doesn't match the "daguerreotype" of Joseph.
First, the "daguerreotype" is not a photo of Joseph. No matter how many ways you "zoom and enhance" the photo, there is no detail in the photo that is not perfectly identical to the RLDS painting. The painting and the photo align perfectly, and it is undeniable that the painting is the source for the photo.
The image on the left shows how a bad crop and overexposure of the painting results in the "daguerreotype" of Joseph that we have today. The image on the right shows how much the painting varies from the death mask. The differences are best explained by artistic error, rather than radical changes from injury.
Second, paintings of Joseph produced while he was alive align almost perfectly with the death mask. These two paintings were made while Joseph posed for them. Any website claiming that Joseph's features must have shifted due to fractures is usually doing so to argue for a stronger chin, or to reconcile the death mask with their favorite candidate for a "daguerreotype." There is no reason to doubt the death mask when it conforms so closely with these paintings. He really looked like that, weak chin and all.
It is true that Joseph suffered fractures when he fell. He and Hiram were exhumed in 1928 due to fears that the rising water of the Mississippi river would destroy their secret grave site. Hiram's skull showed a broken maxilla and missing temporal bones. Joseph's skull was missing all of the facial bones. However, this doesn't necessarily mean that any of those bones shifted significantly once they were fractured. As shown above, Joseph's profile was unaffected.
On the left is an illustration made from a photo of Hyrum's skull taken in 1928, with the blue area indicating missing bones. His death mask's profile fits perfectly when tissue depth is accounted for. On the right is Joseph's neurocranium, with Hyrum's facial skeleton adjusted to fit the correct tissue depth of the death mask. Only slight adjustments are necessary to fit Hyrum's skull to Joseph's mask, again demonstrating that the fractures could not have significantly affected Joseph's death mask.
This animation combines the skulls with the death masks, and shows how little variance there would be between Hyrum and Joseph's skulls. This runs contrary to theories put out by websites claiming that Joseph's mask reveals heavy distortion, and requires violently shifted facial bones to produce.
An illustration from photographfound.com exaggerating the fractures and suggesting a stronger chin and shorter face in support of the RLDS painting/daguerreotype. This is what happens when you start from a false premise (that the RLDS image is an actual photo of Joseph) and work backwards, rather than taking all primary evidence into account and working forwards.