How do I compress JPEG XL files?

Run "npx optimo image.jxl" to compress JPEG XL with lossless optimization. For stronger compression, add --lossy. For size reduction through resizing, add --resize followed by a percentage, dimensions, or target file size.

What is the best way to reduce JPEG XL file size?

The two biggest levers are resizing (reducing dimensions to match display size) and lossy compression. Resizing usually has a larger impact than codec-level compression. Sometimes converting to a more efficient format is the best approach.

Compress JPEG XL files

JPEG XL can be excellent for high fidelity and efficient compression, but delivery support is limited. Treat it as an archival format unless you control the client.

Last updated: 2026-03-18

To compress JPEG XL files, run npx optimo image.jxl. Optimo applies ImageMagick-powered compression by default. For stronger reduction, use --lossy or --resize to shrink dimensions — often the single biggest lever for file size.

Start with optimo

First, run optimo on your image file:

npx optimo image.jxl

This is safe: optimo keeps the original if the output isn't smaller.

Two big levers

1) Lossy mode

npx optimo image.jxl --lossy

2) Resize (dimensions)

npx optimo image.jxl --resize w1280

Practical tips

For broad web delivery, convert to WebP/AVIF/JPEG.
JXL can be great for keeping a “high quality master” before generating derivatives.
If you need predictable browser playback, don’t rely on JXL as the only output.

Optimize JPEG XL Resize JPEG XL JPEG XL format guide

Consider converting

Sometimes the best compression is picking a better delivery format.

JPEG XL → PNG JPEG XL → JPEG JPEG XL → WebP JPEG XL → AVIF JPEG XL → HEIC JPEG XL → GIF

Popular conversions

Convert PNG to JPEG XL Convert JPEG to JPEG XL Convert WebP to JPEG XL Convert AVIF to JPEG XL Convert HEIC to JPEG XL Convert JPEG XL to PNG Convert JPEG XL to JPEG Convert JPEG XL to WebP

Frequently asked questions

How do I compress JPEG XL files?: Run "npx optimo image.jxl" to compress JPEG XL with lossless optimization. For stronger compression, add --lossy. For size reduction through resizing, add --resize followed by a percentage, dimensions, or target file size.
What is the best way to reduce JPEG XL file size?: The two biggest levers are resizing (reducing dimensions to match display size) and lossy compression. Resizing usually has a larger impact than codec-level compression. Sometimes converting to a more efficient format is the best approach.