The ending IMG identifies a file containing a bitmap image created with the early GEM Paint graphics software. Digital Research developed in the 1980s a graphical user interface (GUI) called GEM, which was mainly used on the Atari ST (TOS), but also on the PC.
At GEM, Digital Research also provided the applications GEM Paint and GEM Draw.
Most often resolving problems with opening IMG files is very simple. Just install an appropriate program that supports such files. All of the listed programs support IMG files, but may vary in offered function and purpose. Some programs may be capable only of viewing contents of IMG files or offer file conversion options, but may not be capable of editing such files.
It is possible that although a compatible program has been installed on user’s system, it is not used by the system to open it. This may happen because no default application was associated with this type of files. To associate IMG files with given application, select "Open with" from drop-down menu (accessed by right-clicking on the file). Then select from the list the program or application you want to be used to open this type of file. If the Apple Disk Utility applications is not on the list, select "Browse" option in order to manually locate the directory where Apple Disk Utility has been installed.
Sometimes problems with opening IMG files may not lie with the application itself, but can arise due to other causes, such as: