The JPEG XL Image Coding System (JPEG XL, sometimes shortened to JXL) is an image format that supports both lossy and lossless compression. It was developed by the Joint Photographic Experts Group (JPEG), Google and Cloudinary. It is a free and open standard defined by ISO/IEC 18181. The standard consists of four parts that cover the Core coding system, File format, Conformance testing, and Reference software, respectively.
JPEG XL features a lossy compression mode called VarDCT built on block-based transform coding, which is similar to — but significantly improves and expands upon — the compression method of JPEG, and a modular mode that allows different features of the format to be combined in a "modular" way. Modular mode can be used either for lossless image compression, similar to PNG, or as a means to achieve lossy compression in a different way from VarDCT.
The name refers to the design committee (JPEG), the X designates the series of its image coding standards published since 2000 (JPEG XT/XR/XS), and L stands for "long-term", highlighting the intent to create a future-proof, long-lived format to succeed JPEG/JFIF.
Positioning JPEG XL was designed to become a universal replacement for all established raster formats for the Web. To reach widespread adoption (unlike previous attempts, including several JPEG standards), the designers hope for beneficial network effects by offering the single best option for as many popular use cases as possible. To that end, the format offers significant improvements over all other (established) options with a comprehensive set of useful properties, geared especially towards accessibility over the Web and a smooth upgrade path, in combination with uncompromisingly powerful, yet efficiently computable compression and efficient data representation. Following a study about the most popular JPEG quality on the Web, developers paid special attention to the range with negligible or no perceived loss, and the default settings were adjusted accordingly. Several serious attempts at replacing JPEG that provided poor support for the high end of the quality range have failed.
The JPEG XL call for proposals talks about the requirement of substantially better compression efficiency (60% improvement) comparing to JPEG. The standard is expected to outperform the still image compression performance shown by HEIC, AVIF, WebP, and JPEG 2000.
History In 2015, Jon Sneyers of the company Cloudinary published his Free Lossless Image Format (FLIF) on which he based his standardization proposal, called the Free Universal Image Format (FUIF), that begot JXL's "modular mode". In 2017 Google's data compression research team in Zurich published the PIK format, the prototype for the frequency transform coding mode.
In 2018, the Joint Photographic Experts Group (JTC1 / SC29 / WG1) published a call for proposals for JPEG XL, its next-generation image coding standard. The proposals were submitted by September 2018. From seven proposals, the committee selected two as the starting point for the development of the new format: FUIF and PIK. In July 2019 the committee published a draft, mainly based on a combination of the two proposals. The bitstream was informally frozen on 24 December 2020 with the release of version 0.2 of the libjxl reference software. The file format and core coding system were formally standardized on 13 October 2021 and 30 March 2022 respectively.
Industry support and adoption
Besides Cloudinary, throughout JPEG XL's preliminary implementation in web browsers, various representatives of well-known industry brand names have publicly voiced support for JPEG XL as their preferred choice, including Facebook, Adobe, Intel, the Video Electronics Standards Association, The Guardian, Flickr, SmugMug, Shopify, the Krita Foundation, and Serif Ltd.
Google's stance on JPEG XL was historically ambiguous, as it contributed to the format but refrained from shipping an implementation of it in its browser. Support in Chromium and Chrome web browsers was introduced for testing April 1, 2021 and removed on December 9, 2022 – with support removed in version 110. The Chrome team cited a lack of interest from the ecosystem, insufficient improvements, and a wish to focus on improving existing formats as reasons for removing JPEG XL support.
The decision was met with opposition from the community, with many voicing support for JPEG XL on Chromium's bug tracker. Jon Sneyers, co-author of the JPEG XL spec, has questioned the conclusions drawn by the Chrome team, saying: "I think there has been an unfortunate misinterpretation of the data... which has unfortunately led to an incorrect decision." The decision was also criticized by Greg Farough from the Free Software Foundation, who said it demonstrated Google's "disturbing amount of control" over the web and web browsers.
Mozilla expressed security concerns, as they feel that the rather bulky reference decoder would add a substantial amount of attack surface to Firefox. They expressed willingness to ship a decoder that meets their criteria if someone provides and integrates a suitable implementation. The JPEG XL team at Google Research has offered to write a decoder using the Rust programming language but Mozilla maintains neutral position on supporting JPEG XL.
On November 22, 2022 Pale Moon became the first web browser to release support for JPEG XL to the public with the release of version 31.4.0.
An extension to enable JPEG XL support in Chrome and Firefox became available in January 2024.
Apple Inc. included native JPEG XL file support starting with iOS/iPadOS 17, macOS 14 Sonoma, and Safari 17. iPhone 16 Pro supports JPEG XL compression when capturing ProRAW photos.
Microsoft added support for opening and saving JPEG XL files for Windows 11 24H2 via the JPEG XL image extension in Microsoft Store. Also Microsoft Photos added native JPEG XL support in the 2025.11030.20006.0 build.
The raw image format Digital Negative (DNG) allows image data contained within to be compressed using JPEG XL. Starting in version 1.7.0.0 in June 2023, JPEG XL compression was included as part of the specification. This created a basis for later use as part of "Expert RAW" in Samsung Galaxy smartphones and Apple's "ProRAW".
The PDF Association has stated in the PDF Days Europe 2025 event in September 2025 that they selected JPEG XL as the preferred image format for HDR images embedded for PDF, although no timeline has been given.
In November 2025, following the decision of the PDF Association, the Chrome team reverted their stance on JPEG XL and announced that it was open to contributions to integrate a memory-safe and performant decoder in Blink. The team would require the decoder implementation to have commitment to long-term maintenance to ship it in Chrome. In January 2026, JPEG XL decoding support was merged into Chromium.
Mozilla took a similar stance after months of work, switching from the C++ reference decoder to the same memory-safe and performant decoder in January 2026. May 2026 saw Mozilla deciding to also integrate JPEG XL support into the Firefox release channel starting with Firefox 152, which was released on June 16th 2026.
Both Chrome and Firefox keep JPEG XL support disabled for now, requiring an experimental flag to be set by the user.
Standardization status
Common name Part First public release date(First edition) ISO/IEC Number Formal Title JPEG XL Part 1 30 March 2022 18181–1:2024 JPEG XL Image Coding System — Part 1: Core coding systemPart 2 13 October 2021 18181–2:2026 JPEG XL Image Coding System — Part 2: File formatPart 3 3 October 2022 18181–3:2025 JPEG XL Image Coding System — Part 3: Conformance testingPart 4 5 August 2022 18181–4:2022 JPEG XL Image Coding System — Part 4: Reference software
Features JPEG XL has features aimed at web delivery such as advanced progressive decoding, embedded previews, and minimal header overhead, as well as features aimed at image editing and digital printing, such as multiple layers, CMYK, and spot colors. It also can represent animated images.
The main features are the following:
Compression Lossless encoding for any channel, including alpha. Good for both photographic and synthetic imagery: The format features two complementary modes that can be used depending on the image contents. Computationally efficient encoding and decoding without requiring specialized hardware: JPEG XL is about as fast to encode and decode as old JPEG using libjpeg-turbo and an order of magnitude faster to encode and decode compared to HEIC with x265. It is also parallelizable.
Data reduction Lossy compression possible through the optional quantization of transform coefficients. High image fidelity. Graceful quality degradation across a large range of bitrates: Quality loss is not as abrupt as with older formats. Perceptually optimized reference encoder which uses a perceptual color space, and adaptive quantization.
Versatile and future-proof size limits JPEG XL allows ultra-high-resolution images (up to 1 terapixel) with dimensions of over a billion (230-1) pixels per side. sample precision of up to 32 bits, e.g. for HDR content. up to 4099 channels/components: either one (grayscale), three (RGB), or four (CMYK) main channels. The rest of the channels are optional and can be used to store e.g. alpha for transparency/compositing (either "straight" or "premultiplied"), depth, or thermal data. There can be multiple frames, with non-zero duration (for animation) or with zero duration (for e.g. editing layers in graphics software or multi-page documents). Frames can be smaller or larger than the image canvas and can be blended in various ways. However, regular video codecs are still preferred for encoding realistic moving content. JPEG XL has built-in capability to use various color spaces, transfer curves, and high screen brightness. It is specifically designed to seamlessly handle wide color gamut color spaces with high dynamic range such as Rec. 2100 with the PQ or HLG transfer function.
Data structuring Tiles: Independent coding of sections of a large image by allowing images to be stored in tiles, e.g. for parallelization. Progressive decoding: Mode specifically designed for responsive loading of large images depending on the viewing device's resolution.
Upgrade path JPEG transcoding: Being a JPEG superset, JXL provides efficient lossless recompression options for images in the traditional/legacy JPEG format that can represent JPEG data in a more space-efficient way (~20% size reduction due to the better entropy coder) and can easily be reversed, e.g. on the fly. Wrapped inside a JPEG XL file/stream, it can be combined with additional elements, e.g. an alpha channel. The format is extensible.
Freedom to use Royalty-free licensing of relevant (own) intellectual property/software patents. Production-ready open-source reference implementation available on GitHub under liberal licensing terms (3-clause BSD license).
Technical details
JPEG XL is based on ideas from Google's PIK format and Cloudinary's FUIF format (which was in turn based on FLIF).
The format is mainly based on two encoding modes: VarDCT mode (variable-blocksize DCT) – it is based from the same DCT algorithm as legacy JPEG, but blocks, instead of being restricted to 8×8, come in various sizes (2×2 up to 256×256), non-square shapes (e.g. 16×8, 8×32, 32×64), or can use another transforms (AFV, Hornuss). It is only used for the 3 color channels, which typically use the XYB color space (although YCbCr is also supported in order to recompress legacy JPEG). The VarDCT mode is based on (lossy) PIK. Lossy modes typically use the XYB color space derived from LMS.