ISO image - Computer Definition
A single file that contains the identical content of an optical disc, including the entire folder and file hierarchy. Using an .ISO file extension, ISO images are created to distribute the disc's data over a network in order to burn a CD or DVD at the destination computer. The files in the ISO image are not compressed; however, an ISO utility program is required to identify them and burn the disc with the original file/folder structure. See ISO 9660, UDF, DMG and disk image.