Buttons to determine own Icon sizes with a map level default

I think it would save a lot of time for some module developers, and help with consistency, if the size of a Button were determined by attributes associated with the Button Icon rather than the size of the image. A module and map level default would make this even more swish.

Using the tag to do this in html in chat gave me the idea but as far as I know it isn’t the same with buttons and other stuff in Vassal.