In my organization (Higher Ed) we do a bit of school branding on all of our systems. One being we set a custom background image at the login screens in our labs and classrooms. Did this in Mojave by making our image an heic extension and naming it Mojave then placing it in /Library/Desktop Pictures.

In Catalina that directory moved to /System/Library/Desktop Pictures which you can not write to. I did find a way to do it via disabling System Integrity Protection SIP, making the change then re-enabling it. That is a lot to do on a few hundred machines. Does anybody have a better method to change that image or should I just forget about it?

Thanks in advance.