How to apply updates to .wim images when they are NOT running
Okay, so, when you find someone who is doing it right, like Mark Minasi with his Windows Networking Newsletters, you just have to let people know. His Newsletter #65 came out a while ago, in September of this year, but I wanted to make sure you didn't miss it. In his article, he explains in simple terms how to apply hotfixes to Microsoft .wim files easily, quickly, and free. Just scroll down to "Tech Section: Getting Hotfixes Onto A Windows Image the Easy (and Free) Way" and start reading.
Applying hotfixes to .wim images: http://go.microsoft.com/fwlink/?LinkID=106142&clcid=0x409
How to modify the registry of a .wim image when it is NOT running
Also, you should check out John Baker's blog post about editing the registry in a mounted .wim image. John Baker from my team actually references a blog post by Michael Greene, a Windows Product Specialist. Thanks to John and Michael. Very cool stuff: