What Is JPEG XL (JXL)? Open, Convert and Browser Support

JPEG XL (JXL) is a modern image format designed as a successor to JPG. A .jxl file is typically much smaller than a JPG of the same visual quality, supports transparency, HDR and true lossless compression, and can even repack an existing JPG losslessly. The catch is support: many apps and almost all upload forms cannot open it yet. To use a JXL anywhere, convert it with JXL to JPG or JXL to PNG; to make one, use JPG to JXL.

What is JPEG XL?

JPEG XL is a standard from the JPEG committee (the same group behind the original JPG), finalised in the early 2020s, with a free reference implementation called libjxl. It was built to cover what JPG, PNG and newer web formats each do well:

Smaller lossy files. At the same visual quality, JXL is usually 20–60% smaller than JPG, depending on the image.
True lossless mode, typically smaller than an optimised PNG with exactly the same pixels.
Lossless JPG recompression: an existing JPG can be packed into a smaller JXL and later restored to the identical original JPG file.
Transparency, HDR, wide colour, high bit depth and very large image dimensions.
Progressive decoding, so a low-resolution preview appears quickly while the rest loads.

JPEG XL vs JPG, PNG, WebP and AVIF

	JPG	PNG	WebP	AVIF	JPEG XL
Lossy compression	Good	None	Better	Best for low bitrates	Excellent, especially at high quality
Lossless	No	Yes	Yes	Yes	Yes, usually smaller than PNG
Lossless JPG repacking	n/a	No	No	No	Yes
Transparency	No	Yes	Yes	Yes	Yes
HDR	No	Limited	No	Yes	Yes
Browser support	Universal	Universal	All major	All major	Growing
Upload forms	Universal	Common	Rare	Rare	Almost never

JPEG XL shines at high-quality photos and archiving. AVIF tends to do well at very small file sizes on the web. For a deeper look at the web formats, see our AVIF vs WebP vs JPG comparison.

JXL browser support

Support has had a bumpy history:

Safari on Mac, iPhone and iPad has opened JXL since 2023.
Chrome tested JPEG XL behind a flag years ago, removed it, and has been bringing it back: Chrome 145 (February 2026) added a new decoder behind a flag, with default-on support following in later 2026 releases.
Firefox has likewise been moving towards enabling it by default during 2026.

Because this is changing quickly, whether a JXL displays for someone depends on their exact browser version. For anything you share widely, keep a JPG copy.

How to open JXL files

Mac, iPhone and iPad: recent versions open JXL in Safari, Photos and Preview.
Windows 11: install the JPEG XL Image Extension from the Microsoft Store to view JXL in Photos and File Explorer. Current Chrome, Edge and Firefox versions may also open it.
Android: support depends on the gallery app. A browser converter is the reliable fallback.
Image editors: several current editors read JXL; older versions usually do not.

If a JXL will not open, convert it. That is often faster than hunting for a compatible app.

How to convert JXL to JPG or PNG

Open JXL to JPG for photos, or JXL to PNG for graphics and anything with transparency.
Choose one or more .jxl files.
Download the converted files, individually or as a ZIP.

The converter uses your browser's own JXL decoder when it has one, and a built-in WebAssembly decoder when it does not, so it works on Chrome, Edge and Firefox even where they cannot display JXL themselves. Nothing is uploaded.

JXL to JPG fills transparent areas with white and uses 92% quality by default.
JXL to PNG is lossless and keeps transparency. HDR or wide-gamut images are reduced to standard 8-bit colour in both outputs.

JPG to JXL: lossy, lossless, and "lossless JPG"

There are three different things people mean by JPG to JXL:

Lossy re-encoding. Decode the JPG, encode the pixels as JXL at a chosen quality. Around 80% gives a much smaller file that looks like a high-quality JPG. This is what JPG to JXL does by default.
Lossless pixels. Set our converter to 100% and the JXL keeps every pixel of the decoded JPG. No further loss, but the file can be larger than the JPG.
Lossless JPG recompression. The reference cjxl tool can repack the JPG's existing compressed data into JXL, typically saving a noticeable chunk of space, and djxl can reconstruct the exact original JPG later. Browser canvas tools cannot do this, because they only see decoded pixels.

If you want option 3, for example to archive a big photo library, use the command line:

cjxl photo.jpg photo.jxl
djxl photo.jxl restored.jpg

By default cjxl uses lossless recompression for JPG input. On a Mac, brew install jpeg-xl installs the tools; on Linux, look for a package such as libjxl-tools in your distribution. Check that a restored JPG matches before deleting any originals.

PNG to JXL

PNGs are lossless and large. PNG to JXL at 100% gives a lossless JXL with the same pixels, usually noticeably smaller, and keeps transparency. Lower the quality for photos saved as PNG to shrink them far more. (On the command line, cjxl image.png image.jxl -d 0 makes a lossless file.)

When to use JPEG XL

Good uses:

Archiving photo libraries where you control the software.
Websites that can serve JXL with a JPG fallback.
High-quality masters with HDR or high bit depth.

Avoid for now:

Exam, job and government uploads (use JPG).
Sending photos to people on unknown devices.
Print shops.

Common mistakes

Renaming .jxl to .jpg. It stays JXL inside and will not open where JPG is expected.
Expecting browser tools to do lossless JPG repacking. Use cjxl for that.
Deleting JPG originals after converting. Keep them until you are sure every app you use opens JXL.
Uploading JXL to a form. Convert to JPG and check the extension first.
Converting personal photos on random upload sites. Our guide to online image tool safety explains why browser-only converters are the safer choice.

JPEG XL is one of the most capable image formats available. Use it where you control the viewer, and convert to JPG or PNG everywhere else.

Questions

How do I open a JXL file?

Safari on Mac, iPhone and iPad opens JXL, and Windows 11 can view it with the JPEG XL Image Extension from the Microsoft Store. If your app cannot open it, convert it to JPG or PNG in the browser.

Can JPG be converted to JXL losslessly?

Yes, with the reference cjxl command-line tool, which repacks a JPG into a smaller JXL that can be turned back into the exact original JPG. Browser converters, including ours, re-encode the pixels instead; set 100% quality there to avoid further loss.

Do browsers support JPEG XL?

Safari has supported it since 2023. Chrome and Firefox have been bringing support back during 2026, so whether a JXL displays depends on your browser version. Most upload forms still do not accept JXL.

How do I convert JXL to JPG?

Open a JXL to JPG converter, choose the .jxl files and download the JPGs. Ours decodes JXL inside the page, so it works even in browsers that cannot display JXL themselves.