What is an ISO Image?

An ISO is a file that contains the complete image of a disc, from sector 0 to the end. Such files are often used when transferring CD/DVD images over the Internet, and are commonly used as a way of offering Linux distributions for download. The latest versions of CentOS, for example, are available from centos.org as ISO images. Once you have an ISO image on your hard drive, you can burn it onto a CD or DVD using one of many ISO-burning software packages. More precisely, an ISO image is an image of an ISO 9660 CD-ROM or DVD-ROM. ISO is short for the International Organization for Standardization. (ISO is not an acronym. Instead, the name derives from the Greek word iso, which means equal.) The ISO 9660 format defines the file system used by almost all CDROMs or DVDROMs for Windows, Mac, Linux and so on. Some ISO-burning applications create plain ISO 9660 images, while others interpret the ISO format as they like. Nero, from Ahead Software, uses the NRG suffix to name its ISO images. ...  more

In computing, an image refers to a single file used as a container to hold a digital replica of an existing file system. A disk image is an image of an entire disk drive, used for backup purposes. An ISO image or .iso file is a container format that holds the file system used on optical disks (CDs or DVDs) to store programs, movies and other multimedia content. ISO is a formatting standard set by the International Standards Organization. The ISO format is not used with audio CDs. ISO images will be familiar to anyone who has made copies of software CDs or DVDs. DVD burning software is used to extract the contents of a CD or DVD, creating a single .iso file. This file can be burned to a new disc, or it can be stored and used directly from the hard drive. It can be very convenient to store an operating system (OS) CD on a computer as an ISO image. If you need to make changes to the OS, such as install additional features or repair the system, you won’t have to hunt down the original CD. ...  more

In the context of files and programs, an "image", whether an ISO, floppy, or other media image, is simply a file that can be used as a virtually identical copy of the original media. This file not only contains individual data files, but it also contains track and sector information and arranges all this information in a file system, just like disk media. Image files, unlike normal files, are usually not opened; rather, they are mounted. An ISO image is simply a CD-ROM image saved in ISO-9660 format. A full description of this format is available here. ISO images are mainly used as source files from which to create CDs. Once you download the image, you can use CD burning software to recreate the physical CD-ROM install media.  more

An ISO image is created by a particular software and is the replica of an existing file system. This image can include the whole contents of a DVD-ROM or a CD-ROM. The program that will be used to open, create, edit and extract the DVD image file will allow the users to convert the extracted contents into an ISO image that will burn the exact contents into a DVD again.  more

An ISO image is basically an electronic copy of an entire CD. This single file will have all the files, folders, volume labels and other details of an entire CD. This single file can be used by any CD burning software with total confidence.

An ISO image is basically a "map" of where data goes on a CD. A CD burning program uses an ISO image to write data bit by bit to a CD. ISO images can also be used in software that emulates a CD drive, so that you don't need a physical CD.  more

In the context of files and programs, an "image", whether an ISO, floppy, or other media image, is simply a file that can be used as a virtually identical copy of the original media. This file not only contains individual data files, but it also contains track and sector information and arranges all this information in a file system, just like disk media. Image files, unlike normal files, are usually not opened; rather, they are mounted. An ISO image (.iso) is simply a CD-ROM image saved in ISO-9660 format. ISO images are mainly used as source files from which to create CDs. As an example, most distributions of Linux release ISO images of the installation CDs. These images are usually available from anonymous FTP servers. Once you download the image, you can use CD burning software to recreate the physical CD-ROM install media.  more

In the context of files and programs, an "image", whether an ISO, floppy, or other media image, is simply a file that can be used as a virtually identical copy of the original media. This file not only contains individual data files; it also contains track and sector information and arranges all this information in a file system, just like disk media. Image files, unlike normal files, are usually not opened; rather, they are mounted. An ISO image is simply a CD-ROM or DVD image saved in ISO-9660 format. ISO images are mainly used as source files from which to create media. As an example, most distributions of Linux release ISO images of the installation media. These images are usually available from anonymous FTP servers (such as Indiana University's ftp.ussg.iu.edu server). After you download the image, you can use CD-burning software to recreate the physical CD-ROM/DVD install media.  more

http://www.iso.ch/iso/en/ISOOnline.openerpage Quickie: It's an image file containing many files, similar to a zip file. iso's are usually used to create bootable cd's.  more