What Is JPEG XL & How It Compares To Other Formats

The internet’s always been about getting information as quickly and efficiently as possible; hence, there’s always room for improvement in both content and media assets, such as images. There’s no shortage of image formats besides the common ones such as JPEG, PNG, WEBP, etc. They’re useful for encoding, storing, or even compressing digital images and each has its own USP. However, there is a new format in town called JPEG XL, that aims to be better at everything. With iPhone 16 Pro/Max being the first devices to support the format, this could be a new standard very soon.

What is JPEG XL or JXL?

JPEG XL is an image compression format that improves upon older image formats like JPEG, PNG, and WebP. It is based on Google’s PIK and Cloudinary’s FUIF image formats. The main goal behind its development is to improve compression efficiency while preserving the image quality so that it can be used in everything from the internet to professional photography.

JXL promises about 60% less file size compared to a JPEG with the same visual quality, 20% smaller lossless JPEG transcoding, and 35% smaller than PNG (50% smaller for HDR). These are quite significant reductions. Here are a few examples of JPEG XL relative to other file formats so you can see the difference yourself. Oh, and JXL is backwards-compatible as well.

As mentioned earlier, JXL was created in 2018 by combining Google’s PIK and Cloudinary’s FUIF. Support for the format soon made its way to Chrome and Firefox in 2022. But it was later removed from Chrome because its developers thought it wasn’t worth it. As of writing this, JPEG XL is supported on Safari and on all the latest Apple devices, Linux, and creative software like GIMP, Krita, and Adobe Lightroom, among others.

What Is the File Extension for JPEG XL?

JPEG XL images use the file extension .jxl. Since it isn’t widely used, your image viewer might not be capable of displaying JXL images. Hence, to view the differences in quality between JXL and other formats, Darktable, Affinity, Photoshop, and Lightroom.

JPEG XL vs JPEG vs PNG

A typical JPEG XL image may retain similar or better quality than JPEG but in 20-30% smaller file sizes. JPEG XL is also better at handling artifacts compared to JPEG. The latter usually compresses a lot to reduce the overall file size, thereby introducing artifacts and the image quality taking a severe hit.

JPEG XL supports both lossless and lossy compression. When compared to lossless PNGs, lossless JPEG XL images can sometimes be smaller but almost indistinguishable from PNGs.

Besides, JPEG XL supports transparency and has more color depth (32-bit float VS 16-bit). Combined with lower file size, expect PNGs to go out of business anytime soon, at least across the internet.

JXL even trumps JPEGLI, an image format backed by Google, as it again retains much more detail while maintaining a higher compression ratio.

JPEG XL vs WebP

WebP seems to be the go-to image format for many publishers on the internet, and for all the valid reasons. Both offer great lossy compression without any hit on the image quality, but JXL scoots past the WebP format thanks to more compression and better color depth.

However, WebP is still a tad bit faster than JPEG XL when it comes to encoding and decoding. As a result, the web may not completely switch to JXL when it comes to loading times.

JXL vs Other Formats: Benchmarks and Tests

We need a few examples to better understand the improvements that JXL brings to the table compared to other formats. Fortunately, the folks over at Cloudinary and Fastly have us covered with their benchmark results.

Shown below is a plotted image from ssimulacra2 of the compression JXL achieves after converting from PNG compared to other formats like JPEG, AVIF, and WebP. The time (in ms) is on the Y axis, whereas the file size is on the X axis. As you can see, JXL trumps all formats almost all the time with WebP coming second, followed by AVIF and JPEG.

The encoding times are a different story, though, with WebP sometimes achieving much faster encoding times consistently. Both JXL and AVIF encoding times are almost similar, but on average, AVIF does seem to be leading a bit.

To differentiate how JPEG XL is different to other image formats, here are some image examples from the good folks at Cloudinary. WordPress might compress these even further, but you should be able to see the differences.

You can observe that the JPEG XL is much closer to the PNG image with almost no visual difference. The JPEG image is the worst with lots of visible color banding, followed by WebP, which is usable but still has some banding.

JPEG XL vs All Major Image Formats

JXL support is still expanding and hasn’t made it to all platforms and apps yet. However, we soon expect all major platforms to adopt it and your internet browsing experience may get more colorful and sharp with fewer artifacts and more details.

The image format is currently supported in a lot of software like GIMP, Adobe Lightroom, Krita, FFmpeg, ImageMagick, Firefox (flag), and Edge (flag).

Best Features of JXL

There’s a lot to take away from the above comparisons, so let’s paint a clear picture of why JXL is so significant when it comes to lossy and lossless compression compared to other formats.

• JXL achieves higher compression with 20-30% lower file sizes.
• It supports both lossless and lossy compression without any significant hit to quality.
• JXL has a wider color gamut, so images compressed from, say, PNG to JPEG XL will appear more punchy when compared to JPEG.
• JPEG XL is backward-compatible with JPEG
• JXL has no patent restriction, so any app can use it, driving wider adoption.

JXL: Pros and Cons

While there are lots of advantages of using JXL over JPEG, AVIF, and WebP, there are a few downsides.

If JPEG XL is So Good, Why Isn’t It Widely Adopted Already?

That’s a nice question, and the answer will teach you a thing or two about why having a monopoly is such a bad thing. In 2022, Chrome developers unexpectedly removed JPEG XL because they didn’t think it was the future. One of the creators of JPEG XL, Jon Sneyers, was told the decision was made after a few test results, which convinced the developers that it was not worth it.

Jon pointed out a few flaws in the Chrome team’s testing, but those were ignored. Since Chrome is THE most popular browser, the lack of support from Google slowed down the adoption of JPEG XL. This was until Apple added support for JPEG XL across its devices.

In the Interop project conducted by browser giants like Apple and Google in 2024, JPEG XL received the top vote share with 646 reactions compared to competitors. However, to JPEG XL developers’ surprise, their proposal didn’t get a selection. It’s believed that Google was the one who opposed the proposal.

What are your thoughts on the JPEG XL image format? Let us know in the comments below.