A system image is an exact copy of a drive. By default, a system image includes the drives required for Windows to run. It also includes the operating system, your files, programs and system settings. You can use a system image to restore the content of your computer if your hard disk or your computer crashes. Restoration from a system image, is done as a whole, you won't be able to choose individual items to be restored.
Procedure under Windows 8.1:
Press the Windows key + X > Control Panel.
Select the Windows 7 File Recovery.
Click on "Create a system image".
Choose the drive to perform your backup and click Next.
The procedure may take a few minutes.
Click on Start backup.
Once the image is created, the utility allows you to create a system recovery disc.
If you have not yet created it, click Yes.
The system recovery disk is necessary load the image to your disk.
The image file will be stored in a folder named WindowsImageBackup.