An image backup is a complete copy of a hard disk or other media. The copy is complete in that it can be restored to an empty hard drive – for example, a replacement hard drive – the result being a hard drive containing everything from the original.
There are, of course, nuances to and even disagreement on the term’s meaning.
An image of a hard disk most commonly refers to a copy of all files, folders, and overhead information stored on the disk, including the information required to boot.
Another less common definition is that an image is a copy of every sector on the disk, including those not used, and their physical layout. This is more commonly referred to as a “clone“. See What’s the Difference Between a Clone and an Image? for a more exhaustive comparison and detailed definition.
The term image can be applied to either a partition or an entire hard disk. While making image backups of specific partitions can have value, only an image backup of the entire hard disk can be used to restore to a replacement hard disk.« Back to Glossary Index