Can I join the master to a domain before imaging?

The short answer is no.

The long answer is more complicated.... you *could* but you would end up having to remove it from the domain upon deployment and then re-add it to the domain. Unless the image is a backup, at which time you would be ok. SO it really depends on what you are doing with the image.

Backup = Yes
Deployment = No

If you want the geeky details, let me know and I will give you the 101 of why it will not work in deployment.