If you already have a system image for a computer and are creating a new one for the same computer, the new system image will overwrite the old one. System images are saved in the format of drive\WindowsImageBackup\computer name\. If you're saving your system images in a network location, you can only keep the most current system image for each computer. To help conserve disk space, delete older system images. On internal and external hard drives, older system images will be deleted when the drive runs out of space. You can keep several versions of system images.
Keeping different versions of system images If you save the system image on a hard drive or USB flash drive, it must be formatted to use the NTFS file system. Note: To create a system image of a drive, it must be formatted to use the NTFS file system.