JPEG XL vs. AVIF: Which Format Should Websites Use?

Which format makes smaller web images?

For lossy photos, AVIF is usually the smaller choice in the comparison published in 2026. At default encoding effort, the article reports that JPEG XL files are typically 15–25% larger than equivalent AVIF files. At maximum effort, the reported gap is typically 6–20%. ¹

Those are typical results, not a rule for every image. The analysis reports outliers where JPEG XL comes close to AVIF or produces a smaller file. It also says the encoder—the software that compresses an image—can change JPEG XL results substantially. ¹

• For a typical lossy photo, start by testing AVIF. ¹
• For an image where file size matters greatly, compare both formats on that image. ¹

Which format looks better?

File size alone does not settle image quality. The supplied 2026 comparison gives results for several image types, but the research provided here does not give a single quality score or a universal winner for every picture. ¹

A practical comparison should look at the actual image at the size and quality level intended for the website. Different pictures can respond differently to compression, so a result from one photo should not be treated as a guarantee for another. The earlier comparison source describes its own analysis as unscientific, which is a reason to treat individual benchmark results cautiously. ²

What about screenshots, illustrations and transparency?

The 2026 comparison reports a clearer advantage for AVIF with screenshots and illustrations. In its tests, JPEG XL files were typically 30–90% larger at default effort and 20–70% larger at maximum effort. ¹

It also reports AVIF as much smaller for images with transparency, though the result varies with the JPEG XL encoder and image detail. The source says lossy AVIF can handle screenshots and illustrations well; lossless compression is only necessary when an exact, bit-for-bit match is required. ¹

• For screenshots and illustrations, test AVIF first. ¹
• For transparency, compare the actual output; encoder choice can matter. ¹

Do browsers support JPEG XL and AVIF?

The 2026 article says JPEG XL has landed in all major browsers. ¹ That is a broad statement, not a detailed list of browser versions or device support. The supplied sources do not provide a current, browser-by-browser compatibility table for either format.

Older information can give a different impression. A 2023 comparison noted that many browsers supported AVIF while Chrome had dropped JPEG XL support at that time. ² That report reflects the situation described in 2023, not the later claim in the 2026 article.

• Check current browser support for the audience and devices your site serves.
• Do not rely on the 2023 browser-support description as a current status report. ²

How should a website choose between them?

For a site choosing one format for lossy images, AVIF is the stronger starting point in the supplied 2026 comparison, especially for photos, screenshots, illustrations and transparency. ¹ JPEG XL may still be worth testing when a particular image compresses unusually well or when a site’s image workflow makes it useful.

The comparison does not establish one best format for every site. Results depend on image content, encoder and settings. The research provided also does not set out a complete deployment guide, so check compatibility and image quality in the site’s own workflow before changing formats.