Images can be serviced either online or offline.

• Online: An online image is booted into the operating system, and changes are made while it is running. This can be done before Sysprep is run, or it can be done in the Sysprep Audit Mode.
• Offline: An offline image is not running but instead is an image that is stored in a .wim file. The image can be extracted from the image file in a process referred to as mounting the image. Once it is extracted, files within the image can be modified and packages can be added.