what is a mdi file format
MDI stands for Microsoft Document Imaging format. This TIFF-based file format is designed to store images by page layout using Office Document Imaging, which can save files as MDIs and TIFFs. TIFF files are widely compatible, but MDI files only open with Office Document Imaging, which can be a problem when you have to share MDI files. The best solution is to save them as TIFFs to begin with, but that's not much help if you're the one trying to open MDI files without Office. MDI Viewer by HAN Software opens and displays MDI and TIFF images without having Office, Adobe Acrobat, or any other big-bucks, big-box wares.