Suggestion on how to deliver the base image (windowsservercore)

Our software is deployed on customer side, which means we must deliver the base image, i.e. windowsservercore, which is very large. Unfortunately, not all of our customer have access to the internet, so we cannot just pull the base image from Docker hub on customer side. We used to deliver our software in disks, but the base image is so large that at least 3 more disks is needed to fit it in.
Any suggestions on our case?

memory card, disk drive?