Multi Picture Format Compatible file
If you have files on your computer that have the .mpo file extension then these are Multi Picture Format Compatible files that have been created using a digital camera such as the FinePix Real 3D W1 which is capable of taking 3D photographs.
This format has been proposed as a open standard by CIPA and consists of multiple JPEG files with thumbnails and metadata.
» MPO Toolbox
How to open .mpo files?
Software to open .mpo files
What are .mpo files