The ISO/IEC 10918-x series establishes guidelines and specifies requirements for coding of continuous-tone still images. Rec. ITU-T T.81 | ISO/IEC 10918-1, also known under the name JPEG, specifies the codestream format and the decoding process. It is designed primarily for compression of continuous-tone photographic content. Rec. ITU-T T.873 | ISO/IEC 10918-7 provides reference software for Rec. ITU-T T.81 | ISO/IEC 10918-1. The software has been successfully compiled and tested on Linux and Windows operating systems and conforms to the decoder requirements specified in Recommendation ITU-T T.83 | ISO/IEC 10918-2. It has also been tested for conformance to Rec. ITU-T T.86 | ISO/IEC 10918-4 and ISO/IEC 18477-4. This 2nd edition updates reference software A to version 1.59 and reference software B to version 2.0.x. These versions do not include any new features; they correct implementation errors and improve the overall stability of the software.