Split a Windows image file (.wim) to span across multiple DVDs:
https://msdn.microsoft.com/en-us/windows/hardware/commercialize/manufacture/desktop/split-a-windows-image--wim--file-to-span-across-multiple-dvds
WinPE: Store or split images to deploy Windows using a single USB key:
https://msdn.microsoft.com/en-us/windows/hardware/commercialize/manufacture/desktop/winpe--use-a-single-usb-key-for-winpe-and-a-wim-file---wim?f=255&MSPPError=-2147217396