or JPEG]: Abbreviation for Joint Photographic Experts Group. 1. A standardized, if relatively lossy, file format for transporting, storing, and/or displaying data representing still images and graphical data. Note: Along with .gif, it is one of the most common ways that photos are moved over the Web. 2. Images compressed with the JPEG format and identified with the .jpg or .jpeg file-name extension. 3. An international standards group functioning under ISO and IEC developing an international consensus on an image compression algorithm for continuous-tone still color pictures.