How to convert .img files to .mp4 format.
Converting Disc Image Data Files directly to MPEG-4 Videos (.img to .mp4 conversion) is possible and should be quite straightforward.
Use a DVD ripper software or (online) conversion tool, such as the DVDFab or Nero Multimedia Suite, which allow users to transform IMG files into MP4.
A multimedia conversion and burning software
A popular burning and multimedia suite from Nero