To view and extract content from an .img-file the tool 7zip is required. (This guide should also work but slightly different with the 7zip-GUI on Windows).
.img
7zip
To view the content of such a file via CLI on Linux use:
7z l <path/to/file.img>
For example:
To extract a file from an .img-file use:
7z e <path/to/source/file.img> <file-in-img>
This can then look like this: