A file with .img extension is a Garmin Map File that is used by Garmin GPS devices. It contains map/geospatial data for representing map entities such as street names, navigation routes, and points of interest. Users can create customized map data, save it as .img file and load it onto Garmin devices. Garmin alos provides pre-installed map data that is stored on Garmin devices in the IMG file format. IMG files cna be opened using applications such as Garmin Mobile PC, cGPSmapper, MapUpload and GPS Map Manager.
IMG File Format - More Information
IMG files are saved as binary files in Garmin proprietary file format. Information available in an IMG file can be rendered on Garmin GPS units. Some GPS units, supporting autorouting can also use these map files for guidance during navigation like in-cars, on-bike, or during hiking.
GMAP files are similar to a hard-disk image and is based on a filesystem that composes of subfiles for providing functionality for Garmin GPS units. The .GMP subfiles provide a kind-of subdirectory structure despite the .gmap file format being flat.