I was looking for a method to automate Windows 8 client deployment on Azure. It seems important that you Sysprep the image only when it's already running in Azure. My attempts to Sysprep the image locally all failed; I suppose that when booting up again the VM was somewhere stuck at the mini-setup of Windows.
Make sure that the reference machine is configured and ready to Sysprep. Execute Sysprep. It's important to select "Shutdown" because you need to capture the image!
Open a Command Prompt window as an administrator.
2. change the directory to %windir%\system32\sysprep, and then run sysprep.exe.
The System Preparation Tool dialog box appears.
In System Cleanup Action, select Enter System Out-of-Box Experience (OOBE) and make sure that Generalize is checked.
In Shutdown Options, select Shutdown. 5.
Click OK.
Let the system do its task and wait a few minutes until the VM is powered off.
To capture the image click on the machine where you executed Sysprep and click on capture.
Be warned: The original machine (your Golden Image Machine) will be deleted when the image has been captured.