Files with the .MPO extension contain multiple images in the JPG format, distributed according to a current specification, and contained in a single file, creating a three-dimensional image. It is usually a stereoscopic image, containing two standard images, often taken by a two-lens digital camera, such as those from the Fujifilm FinePix Real 3D series. The format allows for viewing images on devices that support 3D, such as 3D TVs, as well as transforming the image into an anaglyph, somewhat of a digital bas relief, for later viewing using red-and-blue 3D glasses.

The MPO format was introduced by the Camera & Imaging Products Association, abbreviated as CIPA, and though it was initially meant for housing two photos, it currently allows for containing multiple images in one file. Another, similar format that uses stereoscopic images is the Stereo JPEG, abbreviated as JPS.