how to convert img back to imovie or QuickTime

I completed an iMovie project a few years ago. After making the copies I needed from it, I saved it as a img file. Now I cannot figure out how to get it back into a viewable movie format. I saw that it converted to VOB files that you normally see with windows operating system. I tried to get it to convert on my windows unit but that to work but it not work for the whole thing.