John Mueller of Google’s Search Relations team has confirmed that Google Image Search and Google Discover still do not support the JPEG XL image format, saying on Bluesky on 15 October 2026: “FWIW if you’re hoping to get images shown in Google Images & as previews in Discover, etc – JPEG-XL is currently not supported.” Mueller linked to Google’s official image format documentation, which lists BMP, GIF, JPEG, PNG, WebP, SVG and AVIF — with no JPEG XL (reported by Search Engine Roundtable on 23 October). JPEG XL, standardized as ISO/IEC 18181, promises up to 50% better compression than traditional JPEG, about 20% smaller lossless recompression of legacy files, plus HDR and wide-gamut support — so publishers converting to .jxl trade smaller files for invisibility in two of the web’s biggest image traffic sources.
What the supported-format list says
Google’s official image documentation remains the practical reference for SEOs and publishers: BMP, GIF, JPEG, PNG, WebP, SVG and AVIF are the formats Google Images and Discover previews support. Mueller’s Bluesky post, with the link to that documentation, makes clear that JPEG XL has not been added. For years Google has pushed WebP and AVIF in its guidance, and those two modern formats remain the company’s endorsed path to better compression within its search surfaces.
The nuance, noted by SEO consultant Glenn Gabe, is that some .jxl files do appear indexed in Google Images — running a filetype:jxl query surfaces them mixed with other formats — even though the format is not officially supported for Images and Discover previews. Indexing and support are not the same thing, and the official line is what counts for reliable visibility.
What JPEG XL offers — and where it stands
JPEG XL (.jxl) was standardized in 2021 as the successor effort to JPEG. Its pitch is a free, open standard combining up to 50% better compression than traditional JPEG, lossless recompression of legacy JPEG files at roughly 20% smaller sizes, and built-in HDR and wide-gamut support. Yet the format has had a bumpy rollout across browsers and tools, and Mueller’s statement confirms the gap persists in Google’s search surfaces too.
That leaves publishers choosing between compression gains and guaranteed discoverability. The formats that Google officially supports — including WebP and AVIF — remain the safe choice for images meant to appear in Google Images results and Discover previews, a trade-off that also echoes elsewhere in visual search, from AI-written summaries in AI Overviews citation cards to the source preferences test in AI Mode citations and links moving higher in AI Overviews and AI Mode.
Why It Matters
Publishers and SEOs weighing JPEG XL for its compression gains risk invisibility in Google Images and Discover, two of the web’s biggest image traffic sources. Mueller’s confirmation gives that risk an official answer: until the supported-format list changes, JPEG XL is not the right call for any image you want Google to show. The supported list — BMP, GIF, JPEG, PNG, WebP, SVG and AVIF — is the practical guide, and WebP and AVIF remain the modern options Google endorses for squeezing file sizes without losing visibility.
Background
JPEG XL was standardized as ISO/IEC 18181 in 2021 as the open-source successor effort to JPEG, offering materially better compression alongside HDR and wide-gamut support. Google has promoted WebP and AVIF in its image documentation for years, and JPEG XL’s rollout across browsers and tools has been uneven ever since. Mueller’s 15 October statement, reported on 23 October, confirms the gap persists in Google’s own search surfaces.
Source: Search Engine Roundtable
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