.IMG File Extension

Disk image used to mount a file system; can be mounted like a disk drive (e.g., an external hard drive), or an optical disc (e.g., a CD or DVD); stored on the hard drive, but is recognized as a disc or hard disk when mounted by the computer.

IMG files were used by Mac OS 9 and earlier versions of the Mac OS. They can still be opened on Mac OS X, but they have been replaced by the newer .DMG disk image format.

NOTE: In some cases, renaming an IMG file's extension from ".img" to ".iso" allows other programs to open the file.

Contains data copied from a CD by CloneCD; typically used for making backup copies of discs; should be saved in the same folder as the .CCD and .SUB files, which are referenced when burning a new CD.

Raster image created by ERDAS IMAGINE, a geospatial data authoring application; contains one or more layers, called bands, which include multiple image tiles that comprise the image; used to store small to very large geographical datasets.

IMG files may contain additional information, such as statistics, ground control points, map information, and image metadata. They also support subsampled raster layers, called pyramid layers, for faster screen display within GIS applications.

IMAGINE images use the ERDAS Hierarchal File Format (HFA) to store raster data.

Data file used by Grand Theft Auto (GTA) III and IV, a game series where players complete missions in urban city environments; contains various game data, including car and unit graphics, weapons, and other game items; often altered to create custom game content.

IMG files have three different file format versions:

1. GTA III and GTA: Vice City: stored with a separate ".dir" file.
2. GTA: San Andreas: combines the ".img" and ".dir" files into a single archive.
3. GTA IV: supports encrypted game data.

File used by Garmin GPS devices; contains map data, such as street names, navigation routes, and points of interest; used to store and upload user-customized and Garmin pre-installed map data onto Garmin devices.

Disk image typically of a 3.5" floppy disk, which usually has a 1.44MB capacity; stores the contents of the disk as a single file that can be virtually mounted on a computer instead of from the floppy drive.

Floppy disk image files are not commonly used anymore since floppy disk drives are no longer included with most new computer systems.

Image file saved in the GEM format; contains a bitmap that allows monochrome, gray scale, and color images; originated from Digital Research, which is now owned by Novell.

GEM files were commonly used on older operating systems, but they are not used frequently any more.