Hello,
Depending on how you have setup the base image, if the base image spits out a desktop and it needs to be added to the domain, then the user authentications will be going to the Domain Controller of the AD, if not being added to the domain, then it will be authenticated with the local users on the desktop. either way, view connection server authenticates the user against the AD to allocate him the desktop from a desktop pool, this has nothing to do with the actual authentication of the user trying to get into the desktop allocated to him/her.
hope this helps.
Thanks,
Pradeep