What Is JPEG XL (JXL)? The Future of JPEG
What JPEG XL Actually Is
JPEG XL, identified by the file extension .jxl, is an image codec finalized as ISO/IEC 18181 in 2022. It was developed by the Joint Photographic Experts Group — the same committee behind the original JPEG standard from 1992 — in collaboration with Google, which contributed technology from its earlier PIK codec, and Cloudinary, which brought in FUIF (Free Universal Image Format). The result is a format designed from the ground up to replace not just JPEG but also PNG, GIF, and even WebP across most practical use cases. The name can be misleading. JPEG XL is not simply a higher-quality JPEG. It is an entirely new bitstream and container format. A .jxl file shares no structural similarity with a .jpg file, which is why older software cannot open it without an update. The codec supports both lossy and lossless compression, HDR (High Dynamic Range) color with up to 32 bits per channel, wide color gamuts including Display P3 and Rec. 2100, alpha transparency, animation, and even layered images — a feature set that previously required formats like TIFF or PSD. One of its most strategically clever features is lossless JPEG transcoding. If you have an existing .jpg file, JPEG XL can re-encode it as a .jxl file that is typically 20–22% smaller, and you can reconstruct the original JPEG byte-for-byte from that .jxl file later. This means photographers and archives can reduce storage costs without permanently discarding their original JPEG data — a meaningful practical benefit that no other next-generation format offers.
How JXL Compression Compares to JPEG, WebP, and AVIF
Compression efficiency is where JPEG XL makes its clearest technical argument. At equivalent visual quality, JXL consistently outperforms the original JPEG by 35–60% in file size, depending on the image content and quality target. That means a photograph that weighs 500 KB as a JPEG might come in around 280–325 KB as a JXL file at a quality level that most viewers cannot distinguish from the original. Compared to WebP — Google's 2010 format that became the web standard for a decade — JXL is roughly 20–30% more efficient at equivalent quality for photographs. WebP still has a significant edge in browser support, but JXL's compression gains are large enough that the tradeoff is worth tracking. The more interesting comparison is with AVIF, the format based on the AV1 video codec. AVIF and JXL trade blows depending on the scenario. AVIF tends to win at very low bitrates (heavily compressed thumbnails), while JXL performs better at medium-to-high quality levels and encodes significantly faster. A benchmark published by Cloudinary in 2023 showed JXL encoding a high-resolution photograph in roughly 0.3 seconds at quality 80 using the reference libjxl encoder, while AVIF required several seconds for comparable quality — a difference that matters enormously for any service encoding images at scale. JXL also handles text, graphics, and illustrations better than AVIF, which can introduce blockiness artifacts on sharp edges due to its video-codec heritage. For a mixed-content document — think a PDF page with both photographs and sharp text — JXL is generally the more reliable choice. Lossless JXL is also substantially more efficient than lossless WebP, making it competitive with PNG on photographic content and superior on many synthetic graphics.
Browser and Software Support: The Honest Picture
This is where enthusiasm needs to meet reality. As of mid-2026, JPEG XL support is widespread but not yet universal, and the gaps matter. On the browser side, Safari added full JXL support in Safari 17 (released September 2023), which covers all modern iPhones, iPads, and Macs. Firefox enabled JXL support by default in Firefox 113 (May 2023). Chrome is the conspicuous holdout — Google removed its experimental JXL support in Chrome 110 in early 2023, citing a lack of 'sufficient interest from the ecosystem,' a decision that generated significant controversy given that Chrome holds roughly 65% of global browser market share. Chromium-based browsers like Edge and Brave followed Chrome's lead and also dropped support. As of this writing, Chrome has not re-enabled JXL, which means a large portion of web users still cannot view .jxl files in their browser without a plugin. On the desktop software side, the picture is better. Adobe Photoshop added JXL import and export support in version 25.0 (released October 2023), accessible via File > Export > Export As and selecting JXL from the format dropdown. GIMP supports JXL via a plugin. Apple's Preview and Photos on macOS 14+ can open JXL files natively. Windows 11 added JXL decoding support through the Photos app in a 2024 update. For professional photography workflows, tools like Darktable, RawTherapee, and Capture One have varying levels of JXL export support. Check the specific version notes before committing to a JXL-based archival workflow, because 'support' can mean anything from full round-trip editing to read-only display.
Who Should Actually Use JXL Right Now
Given the browser support gap, blanket advice to 'switch everything to JXL' would be irresponsible. The format makes strong sense in specific contexts and less sense in others. JXL is an excellent choice for archival storage. If you are a photographer maintaining a library of JPEG files, converting them to JXL using the lossless JPEG transcoding path gives you a smaller archive with zero quality loss and the ability to recover the original JPEG later. A library of 100,000 JPEGs averaging 4 MB each — 400 GB total — could shrink to roughly 310–320 GB in JXL without discarding any image data. At current cloud storage prices, that is a meaningful ongoing cost reduction. JXL is also well-suited for app-based image delivery where you control the client. If you are building a native iOS or macOS app, you can safely deliver JXL assets knowing that Apple's platforms support them natively. The same applies to server-side PDF generation pipelines where the rendering engine is under your control. For general web use, the calculus is harder. If your analytics show that a significant portion of your audience uses Chrome on desktop or Android — which is extremely common — serving JXL without a fallback will result in broken images for those users. The standard approach is to use the HTML picture element with a JXL source and a WebP or JPEG fallback, letting the browser pick what it can handle. This adds implementation complexity but captures the file-size benefits for the growing portion of users on supporting browsers. For email attachments and documents shared with colleagues, JXL is still premature. Most email clients and document viewers do not render JXL, and sending a .jxl file to a non-technical recipient is likely to cause confusion.
Converting Images to and from JXL with CocoConvert
CocoConvert supports JPEG XL conversion in both directions: you can convert common formats like JPEG, PNG, WebP, and TIFF to JXL, and you can convert JXL files back to JPEG, PNG, or WebP for compatibility with software that does not yet support the format. To convert a JPEG to JXL on CocoConvert, upload your file on the conversion page, select JXL as the output format, and choose your quality setting. The quality slider maps to the libjxl distance parameter — a distance of 0 is mathematically lossless, while distance 1.0 is considered visually lossless for most photographic content, and distance 3.0 produces smaller files with minor visible compression at close inspection. If you are unsure, quality 85 on CocoConvert's 0–100 scale corresponds roughly to a distance of 1.0 and is a reasonable default for photographs. For the lossless JPEG transcoding feature — where the original JPEG can be perfectly reconstructed — CocoConvert currently does not expose this as a separate option. This is an honest limitation worth acknowledging: true lossless JPEG transcoding requires the source file to remain unmodified through the conversion pipeline, and CocoConvert's current architecture re-encodes images rather than wrapping the original bitstream. If bit-perfect JPEG preservation is your requirement, command-line tools like cjxl (part of the libjxl reference implementation) with the --lossless_jpeg=1 flag are the appropriate choice. Converting JXL back to JPEG or PNG is straightforward on CocoConvert and useful when you need to share files with colleagues using software that does not yet support JXL. Upload the .jxl file, select your target format, and download the result. Batch conversion is available for processing multiple files at once, which is practical for converting an entire folder of JXL assets to WebP for a web deployment.
Technical Features Worth Knowing About
Beyond compression ratios, JPEG XL has several technical capabilities that distinguish it from older formats and are worth understanding if you are evaluating it for a specific use case. Progressive decoding is one of the most practically useful. A JXL file can be structured so that a low-resolution version of the image is available after decoding only a small fraction of the file data, with quality improving as more data arrives. This is similar to how progressive JPEGs work, but JXL's implementation is more sophisticated — the early preview is a proper downscaled version rather than a blurry full-resolution pass. For web delivery over slow connections, this can significantly improve perceived load time. JXL supports up to 32 bits per channel (compared to JPEG's 8 bits), which makes it suitable for HDR photography and scientific imaging workflows where 10-bit or 16-bit precision matters. It also supports the full range of ICC color profiles, so color-managed workflows that currently rely on TIFF can potentially migrate to JXL with no loss of color fidelity. Animation support in JXL is more capable than GIF and comparable to APNG and WebP animation. Each frame can have its own duration, and the format does not impose GIF's 256-color limitation or WebP animation's occasional compatibility issues. However, for video-like animation at high frame rates, actual video formats (H.264, AV1) will still produce smaller files — JXL animation is best suited for short, looping UI animations or image sequences where single-frame quality matters. Finally, JXL includes a feature called 'extra channels' that allows embedding depth maps, thermal data, or custom per-pixel metadata alongside the main image. This is niche today but positions the format well for computational photography applications where cameras capture more than a simple RGB frame.
Where JXL Goes from Here
The trajectory of JPEG XL depends heavily on what Google does with Chrome. Chrome's market dominance means that any format Google declines to support faces a structural ceiling on web adoption. The stated reason — insufficient ecosystem interest — is somewhat circular, since ecosystem interest is difficult to demonstrate when the dominant browser does not support the format. There is ongoing pressure from the open-source community and from companies like Cloudinary and Shopify that have a financial interest in better image compression, so the situation may shift. Outside the browser context, adoption is accelerating. Apple's full support across iOS, macOS, and Safari is significant — Apple devices account for a large share of premium web traffic and essentially all high-end mobile photography. The addition of Photoshop support means professional photographers now have a clear path to JXL in their existing workflows without switching tools. The ISO standardization of JXL also matters for long-term archival use cases. Standards bodies, government archives, and medical imaging institutions are more likely to adopt a format with formal ISO backing than a proprietary or de facto standard. This positions JXL well for institutional adoption even if its web presence remains constrained by Chrome's stance. For most people working with images today, the practical recommendation is to stay informed rather than make sweeping infrastructure changes. Use JXL for archival storage and native-app delivery where support is solid. Maintain JPEG and WebP fallbacks for web use. Watch Chrome's release notes. The format's technical merits are not in serious dispute — the question is purely one of adoption timing, and that timing is moving in JXL's favor even if more slowly than its proponents would prefer.