Open DMG File

IMG File

IMG file extension is very similar to ISO file extension since both of them store disk images in binary format which contains raw dumps of optical disks. IMG file like ISO contains full backup of original optical disk. IMG and ISO file extensions are frequently interchangeable as both store optical disk images in ISO 9660 or UDF file format but historically ISO became more popular. IMG files have similar problem as ISO is that they don’t store disk tracks information which makes problematic to store images of audio and video disks in this format. Alternative formats like CUE/BIN, , CCD/IMG and MDS/MDF disk image formats are used in that case.

IMG file stores only binary dump of the original optical or floppy disk thus software which mounts this file will need to infer what file system is used based on the binary information in the IMG file.

What makes IMG format slightly different from ISO is that it could be compressed. In that case file extension is typically changed to IMZ.

There are also possible alternative uses of .IMG file extensions:

• IMG file extension could be used to store vector graphics similar to CGM (Computer Graphics Metafile).
• IMG file extension is used for Apple Disk Images. Even though DMG file extension is the most frequently used for Apple Disk Images there are still cases when disk image is stored in IMG file.
• QEMU uses IMG file extension to store raw images of hard drive disks.
• CloneCD generate disk images in IMG files and stores some CloneCD metadata in corresponding CCD files.
• In CUE/BIN disk images BIN files are stored in the same format as IMG files. The only difference is metadata stored in CUE files.