JPEG compression is used in a number of image file formats. 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.he JPEG standard specifies the codec, which defines how an image is compressed into a stream of bytes and decompressed back into an image, but not the file format used to contain that stream. The Exif and JFIF standards define the commonly used file formats for interchange of JPEG-compressed images.