Computer file consisting of the contents of a storage device
A disk image is a snapshot of a storage device's content – typically stored in a file on another storage device.[1][2]
Traditionally, a disk image was relatively large because it was a bit-by-bit copy of every storage location of a device (i.e. every sector of a hard disk drive), but it is now common to only store allocated data to reduce storage space.[3][4]Compression and deduplication are commonly used to further reduce the size of image files.[3][5]
Disk images can be made in a variety of formats depending on the purpose. Virtual disk images (such as VHD and VMDK) are intended to be used for cloud computing,[11][12]ISO images are intended to emulate optical media, such as a CD-ROM.[13]Raw disk images are used for forensic purposes.[2] Proprietary formats are typically used by disk imaging software.
^Kävrestad, Joakim (2017), Kävrestad, Joakim (ed.), "Vocabulary", Guide to Digital Forensics: A Concise and Practical Introduction, SpringerBriefs in Computer Science, Cham: Springer International Publishing, pp. 125–126, doi:10.1007/978-3-319-67450-6_12, ISBN978-3-319-67450-6, retrieved 2023-01-12