Windows Imaging Format
The Windows Imaging Format is a file-based disk image format (as opposed to a sector-based one) used to preserve and distribute a complete copy of a set of files with all its MS-Windows filesystem structure and metadata. It is created with the ImageX command line tool, part of the free Windows Automated Installation Kit (WAIK).
The file name extension
swm is used for images splited into multiple parts.
The variant with the file name extension
Reconstruct.WIM2 is generated as second disk image by Microsoft's recovery drive creating tool
when the option to back up system files to the recovery drive is chosen.
PPKG file extension is used for Microsoft Windows provisioning packages.
WIM images begin with
WLPWM\0\0\0 for the wimlib pipable variant.