What are .IMG files?
IMG files are a raster image format and is one of the main file formats for Digital Elevation Models (DEM). On some computers it may appear that these are compressed zip files however these files are not zipped and can simply be loaded into your GIS Software. Some CAD users report that .IMG files do not work in their software, in this case you can convert the .IMG file to a .TIF file.
How can I convert data from one format to another?
Users have reported that QGIS (free, open source) can be used to do file conversions. There are many reasons one would want to convert from one file format to another, but a majority of the time is because your software does not support the downloaded file format.
- GeoDatabase to Shapefile
- .IMG to GeoTIFF
To do a conversion within QGIS you can load the data you want to reformat, fight click on the layer in the layers box and select "Export" then "Save As". You can then pick the file format you want to save to.