Domain Mapping plugin causing broken images

I am working on a new site for a client built on their Wp Network install. I have the Domain Mapping plugin installed to handle custom domains.

The site is ready to launch, everything is perfect when the domain is {sub}.{mainsite}.com. When I apply the new domain through the domain mapping plugin, then reload the site with the new domain active, all the site images are broken, not displaying. It is worth noting, the broken images are not just related to images uploaded through the Media Library. Images loaded through the Child Theme are also not displaying. The CSS is completely intact, minus the images.

When I remove the custom domain, and reload using just the subdomain, then all the images reappear.

Also worth noting...when the base install was initially built, I had to build it at {mainsite}.us, as the .com address was applied to the old site. I used the Domain Mapping plugin to apply the .com domain to the mainsite and that works fine. It appears that the Domain Mapping is breaking the images for the additional sites built off the WP Network.

I have the most current Domain Mapping plugin in place. Additionally, I just ran the WP updates, so it is the most current WP install.

I need to get this remedied as soon as I can. I really can't afford to go live Monday with broken images. I would love any thoughts and help possible.
Thanks
Matt