How do you reduce the size of a windows 7 offline image after you removed the old 3rd party drivers via DISM?

Question

As the title says I had a Windows offline image that needed a driver package put on it from a CAB file I extracted the CAB file and used DISM to install all the drivers from it recursively. Some time later it has been determined those drivers won't see use anymore. After removing all those drivers the image is still the same size. It was 378MB before adding the drivers, and 1GB after. After removing the drivers using DISM it is still 1GB. So with that said something is lingering.

How can I accomplish the task of reducing the size of the image back to its original size?

Answer 1

Use DISM /Export-Image to create a new WIM and this reduces the size:

/Export-Image: Exports a copy of the specified image to another file. The source and destination files must use the same compression type. You can also optimize an image by exporting to a new image file. When you modify an image, DISM stores additional resource files that increase the overall size of the image. Exporting the image will remove unnecessary resource files.

Dism /Export-Image /SourceImageFile:install.wim /SourceIndex:1 /DestinationImageFile:install2.wim /Compress:maximum