What is JPEG XL and why use it?

JPEG XL (.jxl) is a modern image format that supports both stills and animation with significantly better compression than JPEG, PNG or GIF. It supports lossless and lossy modes, 16-bit colour, transparency, and very large dimensions — a single format for almost every still or animated use case.

Which browsers can display animated JXL?

Native JXL support is still rolling out. As of 2026, Safari supports it natively, Firefox supports it behind a flag, and Chromium browsers can display it via extensions or behind flags. For broadest compatibility, also export an animated WebP or GIF.

Is JXL output from ffmpeg.wasm reliable?

JXL encoder support in ffmpeg.wasm is experimental — your build may not include libjxl. If encoding fails the status box will show the error. Try the animated WebP maker or the GIF maker as fallbacks with universal player support.

How do I order the frames?

Pick all frames at once in the file dialog — most browsers respect the alphabetical order of your filenames. Naming your frames frame-001.png, frame-002.png, etc. guarantees the expected playback order.

Are my images uploaded anywhere?

No. ffmpeg.wasm runs locally in your browser via WebAssembly. Your image files never leave your device.

How small does JXL get?

For natural photos, JXL is typically 20-50% smaller than equivalent JPEG and dramatically smaller than animated GIF for moving content. Actual savings depend on the content type and chosen quality.

Animated JPEG XL Maker

Combine a sequence of images into an animated JPEG XL (.jxl) — set frame delay, output width and loop count.

100% client-side · no upload

Note: JXL encoder support in ffmpeg.wasm is experimental. If encoding fails, try animated WebP instead.

Image frames (JPG, PNG, WebP) — in order Tip: name files frame-001.png, frame-002.png … so the picker keeps order.

Frame delay (ms) Width (px) Loop

Pick 2 or more images to begin.

How to build an animated JPEG XL

Pick all frames in playback order. JPG, PNG and WebP all work as input.
Set the frame delay (100 ms ≈ 10 fps; 40 ms ≈ 25 fps).
Set an output width — 640px is a good default for previews.
Press Build JPEG XL and download.

Common use cases

Modern web animations: Replace bulky GIFs on Safari-served pages with a single JXL.
Photographer portfolios: JXL handles 16-bit photos with high fidelity that GIF cannot.
Documentation captures: A short UI capture stored as JXL is dramatically smaller than equivalent GIF.
Archival storage: JXL's lossless mode is great for keeping a faithful record of an animation source.

よくある質問

What is JPEG XL and why use it?: JPEG XL (.jxl) is a modern image format that supports both stills and animation with significantly better compression than JPEG, PNG or GIF. It supports lossless and lossy modes, 16-bit colour, transparency, and very large dimensions — a single format for almost every still or animated use case.
Which browsers can display animated JXL?: Native JXL support is still rolling out. As of 2026, Safari supports it natively, Firefox supports it behind a flag, and Chromium browsers can display it via extensions or behind flags. For broadest compatibility, also export an animated WebP or GIF.
Is JXL output from ffmpeg.wasm reliable?: JXL encoder support in ffmpeg.wasm is experimental — your build may not include libjxl. If encoding fails the status box will show the error. Try the <a href="/anim/webp-maker/">animated WebP maker</a> or the <a href="/anim/gif-maker/">GIF maker</a> as fallbacks with universal player support.
How do I order the frames?: Pick all frames at once in the file dialog — most browsers respect the alphabetical order of your filenames. Naming your frames frame-001.png, frame-002.png, etc. guarantees the expected playback order.
Are my images uploaded anywhere?: No. ffmpeg.wasm runs locally in your browser via WebAssembly. Your image files never leave your device.
How small does JXL get?: For natural photos, JXL is typically 20-50% smaller than equivalent JPEG and dramatically smaller than animated GIF for moving content. Actual savings depend on the content type and chosen quality.

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