Google Search and Discover Currently Lack JPEG XL Support, Warns John Mueller

By Nana Wu 35 minutes ago

By Tech & SEO News Desk
Published October 20

As modern web browsers rapidly adopt next-generation image formats to improve page-load speeds and visual fidelity, webmasters face a growing technical gap. According to Google Search Advocate John Mueller, Google Images and Google Discover do not yet support the JPEG XL (.jxl) image format.

The revelation, shared on social media platform Bluesky, highlights a temporary yet critical friction point for developers. While browsers like Google Chrome and Mozilla Firefox have recently baked native JPEG XL rendering into their software, Google’s underlying search indexing and discovery algorithms have not yet caught up. For site owners eager to leverage JPEG XL’s superior compression ratios, HDR capabilities, and lossless fidelity, this discrepancy demands careful implementation strategies to ensure visibility across search engines.

Main Facts: The Current State of JPEG XL in Google Search

The core issue stems from a mismatch between web rendering engines and search engine crawlers. While users browsing the modern web on updated desktop and mobile browsers can seamlessly load .jxl assets, Google’s indexing systems remain blind to the format.

According to Google’s official Image SEO documentation and Indexable File Types guidelines, Google Search strictly supports images referenced within the src attribute of standard img tags utilizing specific file formats: BMP, GIF, JPEG, PNG, WebP, SVG, and AVIF. Noticeably absent from this roster is JPEG XL.

Consequently, if a webmaster deploys a standalone JPEG XL image on their webpage, Google Search crawlers cannot process, index, or serve it within Google Images. Furthermore, because Google Discover relies heavily on robust meta-tags (og:image) and structured data (Schema.org) pointing to supported formats, relying solely on .jxl risks cutting off a vital source of referral traffic.

However, webmasters do not need to avoid the format entirely. By adopting progressive enhancement techniques—specifically leveraging the HTML <picture> element—developers can safely serve JPEG XL to supported browsers while falling back on a Google-friendly format like JPEG, WebP, or AVIF for crawlers and older browsers.

Chronology: Browser Adoption vs. Search Engine Lag

The current conversation surrounding JPEG XL was catalyzed by a wave of recent browser updates rolling out through the fall.

  • September 23: Google initiated early stability updates for Chrome, rolling out JPEG XL support to a small percentage of users ahead of a wider release.
  • October 6: Google officially began rolling out Chrome 155 globally, bringing native JPEG XL support to its massive user base.
  • October 13: Mozilla followed suit, launching Firefox 158 with full native support for the JPEG XL format.
  • October 15: Addressing confusion among web developers regarding these updates, Google Search Advocate John Mueller took to Bluesky to clarify Google’s search-side stance.
  • October 20: Documentation checks across Google Search Central confirmed that no updates or additions regarding JPEG XL had been made to the platform’s image SEO guidelines or changelogs.

This timeline illustrates a familiar historical pattern. A similar gap occurred with AVIF, another next-generation image format. Chrome introduced AVIF support in August 2020 (Chrome 85), but it took nearly four years—until August 2024—for Google to formally announce that AVIF was fully supported across Google Search and Discover.

Supporting Data: The Technical Case for JPEG XL

To understand why developers are eager to adopt JPEG XL despite current SEO limitations, one must look at the technical metrics touted by browser vendors and compression experts.

  • Compression Efficiency: The Chrome developer team reports that JPEG XL provides 30% to 50% better compression than standard baseline JPEG files, significantly reducing page weight without sacrificing visual quality.
  • Lossless & HDR Capabilities: Unlike legacy formats, JPEG XL excels at lossless compression and natively supports High Dynamic Range (HDR) content, making it an ideal candidate for high-fidelity photography and archival imagery.
  • Ecosystem Footprint: Apple’s Safari browser paved the way for mainstream platform adoption by introducing JPEG XL support in iOS and macOS with Safari 17 back in 2023. With Chrome and Firefox now on board, browser-side support is robust, even though tracking platforms like webstatus.dev currently categorize its web availability as "limited" due to laggards like Microsoft Edge.

Google’s engineering teams have actively recommended that developers test both AVIF and JPEG XL to determine which best serves their specific audience requirements, noting that JPEG XL shines brightest in use cases demanding lossless compression and absolute color fidelity.

Official Responses: John Mueller and Barry Pollard Clarify Best Practices

The dialogue regarding JPEG XL’s search compatibility unfolded publicly on Bluesky, providing clear guidance directly from Google representatives.

In his October 15 post linking to Google’s image SEO documentation, John Mueller stated directly:

"FWIW if you’re hoping to get images shown in Google Images & as previews in Discover, etc – JPEG-XL is currently not supported"

This prompted Barry Pollard, a Google Chrome Developer Advocate, to step into the conversation. Pollard raised a crucial practical question for site architects: if JPEG XL is entirely new to Chrome and Firefox, what is the best way for developers to protect their search visibility? Specifically, Pollard asked whether Google Search would properly handle fallback options nested inside an HTML <picture> element.

Mueller confirmed that standard progressive enhancement practices will satisfy search crawlers:

"The picture element includes an img element, so that would work for any search engine (or other page parsing setup). I have not heard of any problems with people doing this kind of progressive enhancement."

Google’s own published documentation supports this approach. According to Image SEO best practices, Google can successfully parse and identify images nested within a <picture> tag as long as a valid, supported fallback URL is provided within the fallback img element’s src attribute.

Implications: Actionable Takeaways for Webmasters and SEOs

For digital marketers, front-end developers, and SEO professionals, the lack of native JPEG XL support in Google Images and Discover requires a strategic, defensive approach to site design.

1. Avoid Naked .jxl Implementations

If you link a .jxl file directly within an img tag’s src attribute, Googlebot will not be able to index it. This means the image will be entirely disqualified from appearing in Google Image search results, and it may fail to populate visual cards in Google Discover feeds.

2. Embrace the HTML <picture> Element

To harness the bandwidth-saving power of JPEG XL without sacrificing search traffic, webmasters must utilize the <picture> tag architecture. By serving JPEG XL as the primary <source>, but placing a legacy-supported format (such as JPEG, WebP, or AVIF) inside the fallback img tag, you satisfy both modern browsers and search engine crawlers simultaneously.

<picture>
  <source srcset="image.jxl" type="image/jxl">
  <source srcset="image.avif" type="image/avif">
  <img src="image.jpg" alt="Descriptive alt text" loading="lazy">
</picture>

3. Audit Open Graph and Schema Markup

Google Discover relies heavily on metadata to generate thumbnail previews. Ensure that your og:image meta-tags and JSON-LD Schema.org structured data point exclusively to Google-supported formats (JPEG, PNG, WebP, or AVIF) rather than .jxl URLs. Providing a .jxl link in your structured data risks breaking thumbnail generation for Discover feeds.

Looking Ahead: When Will Google Index JPEG XL?

As of press time, neither John Mueller nor official updates on the Google Search Central blog have provided a definitive roadmap or timeline for when Google Images and Discover will roll out native parsing for JPEG XL.

Given the four-year gap between Chrome’s adoption of AVIF and Google Search’s eventual indexation of the format, SEO professionals should not hold their breath for an overnight update. Integrating next-generation formats requires a delicate balance between performance optimization and discoverability. Until Google expands its official file-type whitelist, webmasters must rely on smart fallback strategies to keep their sites fast for human visitors and fully indexable for search bots.

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