Multi-Picture Format (also known as MP, MPO, or Multi-Picture Object) is a multi-image extension of the JPEG image format. It is most often used for stereoscopic images, or as a way to include an unusually large thumbnail image. (Most JPEG thumbnail formats are limited to 64KB, but MP supports far larger thumbnails.)
An MP file contains two or more images in JPEG format. When viewed in a JPEG viewer that does not understand MP format, typically just one of the images will be displayed.
MP files are valid JPEG files, except that they have additional data after the EOI marker.
They contain a JPEG APP2 "MPF" segment. The data in this segment uses a format based on a generalization of TIFF format.