SharePoint Brand Center - Controlling who can see the branding assets

In relation to "However, with the standard organizational assets library, it is possible to manage permissions because it is based on a standard document library.". This won't work either. If we use an image in one of our designs (for example a Cultural Hub) we don't want everyone to use that image across their sites, but we do want everyone to be able to view the site (including the image). If we remove permissions for that image in the Organizational Assets Library, it will give them an access denied error when they try to access the site. When adding images to your site from the Organizational Assets Library, it's not a copy you get, it's linked (so everyone will need read access).