It was simply "Ghost" before Norton bought it and made it more terrible and bloated over time. We (at a computer shop I worked at) used Ghost to build a pre-OOBE image for several common Windows configurations and then just image them to new PCs in a few minutes, then apply the license key afterward.
Symantec left our team - which was basically identical before and after acquisition - pretty much alone beyond adding in some (badly needed) release process and i18n requirements.
Almost the entirety of the growth in the size of the imaging executable, which did get hugely bigger, came from a constant drive to add capability to the NTFS support to match the FAT support, most crucially to allow the images to be edited in Ghost Explorer. The initial NTFS support that Ghost had prior to the Symantec releases was really crude, basically the content in the .GHO file wasn't files, but a raw-ish dump of used disk extents that it tried to always put back in the same place to avoid having to fix up attribute runs, whereas the FAT16/FAT32 content was basically a file archive where all the filesystem allocation metadata got recreated on the fly.
Customers wanted and pushed hard to have NTFS images editable, and that made life really hard - the approach that was ultimately taken meant creating a full read/write NTFS implementation, and those aren't small. And the design of that code interacted really badly with the C++ exception implementation in DJGPP (which before that work had begun, I had warned them about), so that eventually exception frame information was taking up ~25% of the on-disk size of the UPX-compressed binary!
