JXL Converter
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What is JPEG XL?

JPEG XL (file extension .jxl) is a royalty-free image format standardised as ISO/IEC 18181 by the JPEG committee. It handles both lossless and lossy compression, supports HDR, transparency and animation, and can repack existing JPEG files about 20% smaller without any quality loss.

The short version

JPEG XL is a modern still-image format. It was developed by the Joint Photographic Experts Group (the “JPEG” in its name) and published as the international standard ISO/IEC 18181 (JPEG XL overview, jpeg.org). It is meant to be a long-term replacement for the original JPEG from 1992, while also covering what people use PNG, GIF and WebP for.

Files use the extension .jxl and the media type image/jxl.

Where it came from

In 2018 the JPEG committee issued a call for proposals for a next-generation image coding standard. The two leading submissions — Google’s PIK and Cloudinary’s FUIF (Free Universal Image Format) — were merged into what became JPEG XL (Wikipedia: JPEG XL). The core coding system (Part 1) and the file format (Part 2) were published in 2022. The reference implementation, libjxl, is open source under the BSD-3-Clause license.

What makes JPEG XL different

1. Lossless JPEG recompression

This is the feature that sets JPEG XL apart from every other modern format. An existing JPEG file can be converted to JPEG XL without decoding it to pixels: the encoder keeps the JPEG’s original DCT coefficients and stores them more efficiently. The JPEG committee cites savings of about 20%, and the original JPEG can be reconstructed exactly, byte for byte. For the billions of JPEGs that already exist, this means smaller storage with no quality cost and a guaranteed way back. Our JPG to JXL converter uses exactly this path.

2. Two coding modes in one format

JPEG XL contains two complementary encoders:

  • VarDCT, a lossy mode based on variable-size discrete cosine transforms — a much more flexible descendant of the classic JPEG approach, suited to photographs.
  • Modular, used for lossless compression (and for some lossy work), based on prediction and context modelling, suited to graphics, screenshots and anything that must be pixel-exact.

An encoder can mix the two within one image.

3. Progressive decoding

A JPEG XL file can be arranged so that a usable preview appears after only a small part of the file has arrived, and the image sharpens as more data loads. This helps on slow connections and was one of the reasons browser vendors were interested in the format.

4. High fidelity and modern colour

The format supports high bit depths (including floating-point samples), wide colour gamuts, HDR transfer functions, alpha transparency, animation, and extremely large images — up to about a billion pixels per side. That makes it practical for professional photography and archiving, not only for the web.

5. A choice of bare codestream or container

A .jxl file is either a bare codestream (just the image) or an ISO-BMFF-style container that can also hold metadata boxes such as Exif and XMP. Our converter writes a container whenever there is metadata to keep, and a bare codestream otherwise.

How JPEG XL compares in practice

Every image format makes trade-offs. Very broadly:

  • At high quality — the range most photographers care about — JPEG XL is generally regarded as strong, and it is clearly ahead for lossless JPEG recompression, which no other modern format offers.
  • At very low bitrates (tiny, heavily compressed images), AVIF is often considered better.
  • For compatibility, WebP and JPEG still win because almost every device can display them.

We go through these points, with links to independent sources, in JXL vs WebP vs AVIF. We do not publish size or quality numbers until we have measured them ourselves with a documented method.

Can I use JPEG XL today?

On the web, support changed substantially in 2026: Safari has displayed JPEG XL since version 17 (2023), Firefox enabled it in version 158 (October 2026), and caniuse lists Chrome 155 and later as supporting it. Details, dates and caveats are on our browser support page — and because this moves fast, always check caniuse.com/jpegxl for the current state.

Outside browsers, many image viewers, editors and operating systems can open .jxl files, and command-line tools from libjxl (cjxl and djxl) are available for every major platform.

Good uses for JPEG XL right now

  • Archiving JPEG photo collections with lossless recompression.
  • Storing high-quality masters of photos and artwork in less space.
  • Lossless graphics where PNG files are large.
  • Websites, with a fallback format via the HTML <picture> element for browsers that do not support it yet.

Try it

You can convert your own images on the home page or the format-specific pages for JPG, PNG and WebP. Everything happens in your browser.

Sources

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Frequently asked questions

Is JPEG XL the same as JPEG 2000 or JPEG XR?

No. They are different, incompatible formats from the same committee. JPEG XL is the newest, finalised in 2022, and is designed to replace the original JPEG for both photos and graphics.

Is JPEG XL royalty-free?

The JPEG committee designed it to be royalty-free, and the reference implementation libjxl is released under the BSD-3-Clause license together with a patent grant from its contributors. As always with patents, this is not legal advice.

What does the 'XL' stand for?

The JPEG committee uses 'X' in several of its standard names (JPEG XR, JPEG XS); 'XL' is commonly read as 'long-term', reflecting the goal of a format that lasts for decades.

Can JPEG XL replace PNG and JPEG?

Technically it covers both use cases: lossless graphics like PNG and lossy photos like JPEG. In practice that depends on software support, which grew a lot in 2026 but is not yet universal.