A disc image file is a computer file which contains the contents and structure of a disc volume. Alternatively, you can say that disc image file contains an entire data storage device, such as a USB flash drive, floppy disc, tape drive, optical disc, or a hard disk drive. Usually, a disc image is created by making a sector-by-sector copy of the source medium, thereby accurately copy the structure and contents of a storage device independent of the file system. A disc image may span one or more computer files.

Some popular disc file formats are Toast, BIN and VCD

List of Reporting File Extensions and Associated File Formats

Following is a list of Reporting File Formats along with their file extensions.