The MDI file format was created by Microsoft and was first used in their Office XP application suite. The format is very similar to the popular PDF format but is proprietary so the exact specifications have not been released to the public.
The MDI format itself is used to store raster images of scanned documents but uses better compression, resulting in smaller file sizes compared to the popular scanning file format, TIFF.
Despite the smaller file size of the MDI format, it is recommended that you save your scanned documents in the TIFF format which is more compatible with other software packages.
Other .MDI file extensions
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