This article is dedicated to documenting methods of performing drive imaging (also called bare metal backups, or disk cloning). Drive imaging is a complete copy of all information on a drive, necessary to restore all of the data or entire operating system on a drive to the same state it was when the image was created. This is different from imaging a partition, where one is making a copy of an individual partition that resides on a drive, or backing up individual files and folders.

Please ensure you are comfortable with the information discussed before proceeding. Improperly executing a command may result in partial or complete data loss. Please double- or even triple-check your target device to avoid such catastrophic loss.

Source: DriveImaging – Community Help Wiki