Most of the space that is unused does not need to be used
And I think 512x512 is the default texture res size for m&b
Wasted pixels!
512 is mostly the older native items.
1024 is pretty standard for most things now. (e.g. can be: higher for armours, lower for weapons e.g. I use 512x1024 for my swords)
For a mount, 1024 would seem warranted tbh.
Bring me your finest steed and I shall see it to battle!
