Graphics editors that support large number of file formats (for example Adobe Photoshop), should perhaps be able to help you open CIPA Multi-Picture files (.mpo) and export them as common JPEG pictures (.jpg, .jpeg). The unique properties of such files will be lost however. It seems to be pretty rare format nowadays, but still supported in some programs.
Open MPO file Open JPG fileA small program for exploring MPO files
A 3D-photo viewer, editor and batch processor