You can service a Windows® PE image and add or remove packages, drivers, and language packs just as you would any Windows® 7 image using the appropriate driver, package, or international-servicing commands in Deployment Image Servicing and Management (DISM.exe). There are also commands that are specific to a Windows PE image, which you can use to prepare the Windows PE environment, enable profiling, list packages and prepare the Windows PE image for deployment.
For more information about customizing a Windows PE image see, Windows PE Customization How-To Topics
For more information about DISM commands that are specific to a Windows PE image, see Windows PE Servicing Command-Line Options