The original JPEG specification published in 1992 implements processes from various earlier research papers and patents cited by the CCITT (now ITU-T) and Joint Photographic Experts Group. In 2000, the JPEG group introduced a format intended to be a successor, JPEG 2000, but it was unable to replace the original JPEG as the dominant image standard. JPEG/JFIF supports a maximum image size of 65,535×65,535 pixels, hence up to 4 gigapixels for an aspect ratio of 1:1. JPEG files usually have a filename extension of. The MIME media type for JPEG is image/jpeg, except in older Internet Explorer versions, which provides a MIME type of image/pjpeg when uploading JPEG images. These format variations are often not distinguished, and are simply called JPEG. JPEG/ Exif is the most common image format used by digital cameras and other photographic image capture devices along with JPEG/ JFIF, it is the most common format for storing and transmitting photographic images on the World Wide Web. JPEG compression is used in a number of image file formats. JPEG was largely responsible for the proliferation of digital images and digital photos across the Internet, and later social media. The basis for JPEG is the discrete cosine transform (DCT), a lossy image compression technique that was first proposed by Nasir Ahmed in 1972. The term "JPEG" is an initialism/acronym for the Joint Photographic Experts Group, which created the standard in 1992. Since its introduction in 1992, JPEG has been the most widely used image compression standard in the world, and the most widely used digital image format, with several billion JPEG images produced every day as of 2015. JPEG typically achieves 10:1 compression with little perceptible loss in image quality. The degree of compression can be adjusted, allowing a selectable tradeoff between storage size and image quality. JPEG ( / ˈ dʒ eɪ p ɛ ɡ/ JAY-peg) is a commonly used method of lossy compression for digital images, particularly for those images produced by digital photography.
Continuously varied JPEG compression (between Q=100 and Q=1) for an abdominal CT scan