An ISO image file, often referred to as an ISO, is an archive file that contains an identical copy (or image) of the data found on an optical disc, like a CD, DVD, or Blu-ray disc. It essentially represents the entire contents of the disc, including the file system, boot information, and all the data files, in a single file. ISO images are commonly used for backing up optical discs, distributing software, and creating virtual drives. They provide a convenient way to store and share large amounts of data without the need for physical media. The ISO format is standardized by the International Organization for Standardization (ISO), hence the name. When you mount an ISO image, your operating system treats it as if it were a physical disc inserted into a drive, allowing you to access its contents directly. This makes ISO images a popular choice for installing operating systems, software applications, and games.