在电脑中，JPEG（发音为jay-peg, IPA：[ˈdʒeɪpɛg]）是一种针对相片影像而广泛使用的一种失真压缩标准方法。这个名称代表Joint Photographic Experts Group（联合图像专家小组）。此团队创立于西元1986年，1992年发布了JPEG的标准而在1994年获得了ISO 10918-1的认定。JPEG与视频音频压缩标准的MPEG（Moving Picture Experts Group）很容易混淆，但两者是不同的组织及标准。

JPEG本身只有描述如何将一个影像转换为字节的数据串流（streaming），但并没有说明这些字节如何在任何特定的保存媒体上被封存起来。JPEG的压缩方式通常是破坏性数据压缩（lossy compression），意即在压缩过程中图像的品质会遭受到可见的破坏，有一种以JPEG为基础的标准Lossless JPEG是采用无失真的压缩方式，但Lossless JPEG并没有受到广泛的支持。

The Joint Photographic Experts Group is the joint committee between ISO/IEC JTC1 and ITU-T (formerly CCITT) that created the JPEG, JPEG 2000, and JPEG XR standards. It is one of two sub-groups of ISO/IEC Joint Technical Committee 1, Subcommittee 29, Working Group 1 (ISO/IEC JTC 1/SC 29/WG 1) – titled as Coding of still pictures. In the ITU-T, its work falls in the domain of the ITU-T Visual Coding Experts Group (VCEG). ISO/IEC JTC1 SC29 Working Group 1 (working together with ITU-T Study Group 16 – SG16 and previously also with Study Group 8 – SG8) is responsible for the JPEG and JBIG standards. The scope of the organization includes the work of both the Joint Photographic Experts Group and Joint Bi-level Image Experts Group.