These graphics have been digitized at a high resolution, so they can be infinitely, perfectly duplicated. As works of the US government they are inherently unco

These graphics have been digitized at a high resolution, so they can be infinitely, perfectly duplicated. As works of the US government they are inherently uncopyrightable, so there is no legal barrier to copying them either. Thus, these images are completely limitless. Why would you want to introduce artificial scarcity of such a resource?