The GHO extension is used by Norton Ghost 2003 and earlier versions for the image files. Current versions use the extension v2i and do not support the GHO format, they can not restore GHO files.
Symantec's Norton Ghost is a backup utility that creates complete images of disks and partitions. It stores the entire structure and all data in one or more files. The first file of such a backup has the extension gho, all following the file extension ghs.
Norton Ghost allows these backups to be completely written back to a hard disk or to search in the backup and extract individual files.
GHO files can also be password protected and compressed.