`
`JPEG JFIF
`What is it
`
`JPEG JFIF
`
`JPEG
`
`JPEG (Joint Photographic Experts Group) is a lossy compression method standardised by ISO.
`
`JPEG JFIF, which is what people generally mean when they refer to "JPEG", is a file format
`created by the Independent JPEG Group (IJG) for the transport of single JPEG-compressed
`images.
`Status
`
`The JPEG compression format was standardised by ISO in August 1990 and commercial
`applications using it began to show up in 1991. The widely used IJG implementation was first
`publicly released in October 1991 and has been considerably developed since that time. JPEG
`JFIF images are widely used on the Web. The amount of compression can be adjusted to
`achieve the desired trade-off between file size and visual quality.
`
`Progressive JPEG is a means of reordering the information so that, after only a small part has
`been downloaded, a hazy view of the entire image is presented rather than a crisp view of just a
`small part. It is part of the original JPEG specification, but was not implemented in Web
`browsers until rather later on, around 1996. It is now fairly widely supported.
`
`Although the "baseline" variety of JPEG is believed patent-free, there are many patents
`associated with some optional features of JPEG, namely arithmetic coding and hierarchical
`storage. For this reason, these optional features are never used on the Web.
`MIME type
`
`The registered MIME type for JPEG JFIF images is
`image/jpeg
`More information
`
`The JPEG compression specification was also published by the International
`Telecommunication Union (ITU) as Recommendation T.81 and is available in PDF. The
`specification for the JFIF file format is also available, in PDF
`
`There is an informative JPEG FAQ. There is ongoing work in ISO to develop new versions of
`JPEG which give less visible artefacts when the image is compressed.
`
`There is more information about the "lossless and near lossless" JPEG-LS format (and the
`closely related LOCO-I format) from HP. No MIME types have been allocated for this format,
`https://www.w3.org/Graphics/JPEG/
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`Unified Patents Exhibit 1030
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`6/27/2019
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`JPEG JFIF
`and it is not clear whether the lossless and the near-lossless variants will have different MIME
`types.
`
`Chris
`Created: 13 Feb 1996
`Last updated: $Date: 2003/01/09 01:46:31 $
`
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`https://www.w3.org/Graphics/JPEG/
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`2/2
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`Page 2 of 2
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