[HELP] Trying to create a bootable volume image to deploy!

Hey all,

I am in charge of creating a deployable image to refurbish our computers here at work. I have the files on my desktop, and I have made a bootable image before, but I can't seem to make it into a .dmg that I can post to our server. Does anybody have any experience in this?

Recap:

I have a custom bootable image of a volume (includes specialized apps we want to have on our computers, subprocesses, and it creates an admin account.)

I want to package this image (it becomes a folder when duplicated on my desktop) into a .dmg so I can put it on our server and other offices can download it and use it for their own refurbishing.

I don't want to use any paid software, as I'm fairly certain you can do this in Disk Utility...

Thanks