No, when making maps there is a brightness slider that you can adjust to make a map brighter or darker. And yeah frithen is fine, because it uses dark textures underneath mex icons to make the mexes stand out more. It also uses a wider variety of mixed textures so the bright white colour isnt overwhelming. it might even use a lower brightness setting than mapgen, i dont know
If you'd rather not adjust the snow map brightness setting, you could code it so snow maps use darker textures around mex spots
I've just checked and noticed white fire is pretty bright too, but i guess it never bothered me because i know where all the mex are anyway, and its predominantly water and not the insanely bright white