What Is JPEG XL?
JPEG XL (file extension .jxl) is an image format standardized as ISO/IEC 18181 in 2022. It was developed by the JPEG committee (the same group behind the original JPEG) with the explicit goal of being a single format that replaces JPEG, PNG, GIF, and WebP simultaneously. The name "JPEG XL" stands for JPEG Extended Long-term, reflecting its ambition as the long-term successor to the original JPEG.
Unlike WebP (based on VP8) and AVIF (based on AV1), JPEG XL was designed from scratch as an image codec rather than adapted from a video codec. This purpose-built design gives it unique capabilities that video-derived formats cannot easily replicate.
Key Features of JPEG XL
Lossless JPEG Recompression
This is JPEG XL's most unique feature. JPEG XL can take an existing JPEG file and recompress it losslessly, producing a .jxl file that is 20-30% smaller with zero quality loss. The original JPEG can be perfectly reconstructed byte-for-byte from the JXL file. No broadly supported web delivery format in the JPEG/WebP/AVIF fallback chain can do this.
This matters enormously for the billions of existing JPEG images on the web. Converting a JPEG to WebP or AVIF is always a lossy re-encode that introduces additional quality degradation. JPEG XL can shrink those same files without any generational loss whatsoever.
Superior Lossy Compression
At lossy compression, JPEG XL is competitive with AVIF and superior to WebP:
| Format | Size vs JPEG (same quality) | Best At |
|---|---|---|
| WebP | 25-35% smaller | General web use, fast encoding |
| AVIF | ~50% smaller | Maximum compression, HDR |
| JPEG XL | ~60% smaller | High quality, progressive decode, versatility |
At high quality settings (where differences matter most for photography and e-commerce), JPEG XL often outperforms AVIF. The advantage is most pronounced at quality levels above q85 equivalent, exactly where professional and commercial images tend to be encoded.
Progressive Decoding
JPEG XL supports true progressive decoding, where the image loads in increasing quality passes. The browser can display a useful preview of the full image after receiving only 10-20% of the file data. This is similar to progressive JPEG but more efficient.
Neither WebP nor AVIF support progressive decoding. They are all-or-nothing: the browser must download the entire file before displaying anything. For large, high-quality images on slow connections, progressive decoding provides a dramatically better user experience.
HDR and Wide Gamut
Like AVIF, JPEG XL supports HDR (up to 32-bit floating point) and wide color gamuts including Display P3 and Rec. 2020. It also supports the Perceptual Quantizer (PQ) and Hybrid Log-Gamma (HLG) transfer functions used by HDR displays.
Animation
JPEG XL supports animation natively, with features comparable to APNG but with much better compression. Animated JPEG XL files can use lossy or lossless compression and support full alpha transparency.
Other Notable Features
- Transparency: Full alpha channel support in both lossy and lossless modes
- Multiple layers: Native support for layers and blend modes
- Metadata preservation: Full EXIF, XMP, and JUMBF metadata support
- Fast decoding: Designed for single-core and multi-core decoding; faster to decode than AVIF
- Encoding speed: Configurable speed/quality tradeoff; fast modes are comparable to WebP encoding speed
- No royalties: Royalty-free, like WebP and AVIF
Browser Support in 2026
Browser support is JPEG XL's biggest challenge and the primary reason it is not yet the default recommendation:
| Browser | JPEG XL Status (April 2026) |
|---|---|
| Safari (macOS/iOS) | Still-image support enabled by default since Safari 17; feature support is partial |
| Chrome | Decoder reintroduced behind a flag (chrome://flags/#enable-jxl-image-format); disabled by default |
| Firefox | Experimental work exists, but stable Firefox keeps JPEG XL disabled by default |
| Edge | Not enabled by default |
| Opera | Not enabled by default |
| Samsung Internet | Not yet supported |
Safari is the only major browser with JPEG XL enabled by default, and even Safari's support is partial. Chrome removed JXL support in Chrome 110 (2023), then reintroduced a decoder behind a flag in Chrome 145+. Firefox has experimental implementation work, but stable Firefox still keeps JPEG XL disabled by default.
The practical implication: you cannot rely solely on JPEG XL for web delivery in 2026. You need fallbacks. JPEG XL is worth preparing for archival and progressive-enhancement workflows, but AVIF/WebP/JPEG remain the practical delivery chain for most public websites.
JPEG XL vs WebP vs AVIF
| Feature | WebP | AVIF | JPEG XL |
|---|---|---|---|
| Lossy compression | Good (25-35% < JPEG) | Excellent (~50% < JPEG) | Excellent (~60% < JPEG) |
| Lossless compression | Good | Good | Best in class |
| JPEG recompression | No | No | Yes (20-30% savings, lossless) |
| Progressive decoding | No | No | Yes |
| HDR / Wide gamut | No (8-bit sRGB only) | Yes (10/12-bit) | Yes (up to 32-bit float) |
| Animation | Mature | Less mature | Supported |
| Encoding speed | Fast | Slow | Configurable (fast to slow) |
| Decoding speed | Fast | Moderate | Fast |
| Browser support (2026) | 97%+ | 93%+ | Safari only (by default) |
| Royalty-free | Yes | Yes | Yes |
How to Use JPEG XL Today
Despite limited browser support, there are practical ways to use JPEG XL right now:
- Archival storage: Use JPEG XL's lossless JPEG recompression to shrink your JPEG photo library by 20-30% with zero quality loss. You can reconstruct the original JPEG at any time.
- Progressive enhancement: Serve JXL to Safari users and AVIF/WebP to others using the
<picture>element or CDN-based content negotiation. - Native apps: Apple platforms can decode still JPEG XL through system image frameworks on current OS versions.
- Preparation: Generate JXL versions of your image assets if you have a concrete Safari, archival, or testing workflow; keep AVIF/WebP/JPEG fallbacks for public delivery.
Working with JPEG XL in FastEdit
FastEdit supports JPEG XL decoding and encoding in the browser via its WebAssembly-based processing pipeline. You can open .jxl files, convert other formats to JPEG XL, and compare JXL output against WebP and AVIF to see exactly how each format performs on your specific images. FastEdit's normal image pipeline re-encodes pixels locally; for byte-exact lossless JPEG recompression, use a workflow specifically built around preserving the original JPEG bitstream. All processing happens locally in your browser.
The Future of JPEG XL
JPEG XL is technically one of the most capable image formats available in 2026. It compresses better than WebP in many cases, competes with AVIF at high quality, and offers unique features like lossless JPEG recompression and progressive decoding. The main thing holding it back is default browser support outside Safari.
If Chrome and Firefox enable JPEG XL by default, the format landscape will shift. Until then, JPEG XL is best treated as an archival and progressive-enhancement format rather than a single-format replacement for the AVIF-then-WebP-then-JPEG fallback chain.