The way I set the default printers in the labs is to use Group Policy. Whenever a user logs into AD, it reads what Group Policy has to say about what printer that person gets, then applies the default printer based on location. No need to change the image to set that.
On XP it was great because it just worked, but somehow in Windows 7 it is different. It didn’t want to behave. When you log in, it wants to set the default printer to what is first listed. But if you log out and log back in, it will set the correct printer as the default. Not much good for users have to log in twice to get the the correct printers.
After HOURS of trying multiple settings, I finally found this post that says I just need to change 1 settings in the printer policy. WOW. Is that all I really had to do? Somehow that was not needed in XP, but you need it in Windows 7. Why can’t Microsoft just make it the same throughout each build of their OS?