How do I resize JPEG XL files?

Optimo supports three resize modes: percentage (--resize 50%), dimensions (--resize w960 or --resize h480), and target file size (--resize 150kB). Run "npx optimo image.jxl --resize " to resize and optimize in one step.

What is the best resize mode for JPEG XL?

Use dimensions (--resize w960) when you know the display size. Use percentage (--resize 50%) for quick scaling. Use target file size (--resize 150kB) for thumbnails and budgets. Resizing is usually the single biggest lever for reducing JPEG XL file size.

Resize JPEG XL files

Resizing is usually the biggest lever for reducing JPEG XL file size.

Last updated: 2026-03-18

To resize JPEG XL files, run npx optimo image.jxl --resize <value>. Optimo supports three modes: percentage (50%), dimensions (w960), and target file size (150kB). Resizing reduces both dimensions and file size in one step — often more effective than compression alone.

Resize by percentage

Quick way to scale down when you don't know exact dimensions yet.

npx optimo image.jxl --resize 50%

Resize by dimensions

Cap width or height to match how the asset is displayed.

npx optimo image.jxl --resize w960

Use w for width and h for height.

Resize to a target file size

Useful for thumbnails and previews when you want predictable budgets.

npx optimo image.jxl --resize 150kB

Start with a budget you can ship everywhere, then adjust based on quality.

JPEG XL-specific tips

Resize to your max render size before generating final delivery formats.
Use size targets (`--resize 200kB`) for thumbnails derived from a master.
For UI assets, consider SVG/PNG/WebP depending on needs.

Optimize JPEG XL Compress JPEG XL JPEG XL format guide

More image formats

Resize PNG Resize JPEG Resize WebP Resize AVIF Resize HEIC Resize GIF Resize SVG

Frequently asked questions

How do I resize JPEG XL files?: Optimo supports three resize modes: percentage (--resize 50%), dimensions (--resize w960 or --resize h480), and target file size (--resize 150kB). Run "npx optimo image.jxl --resize <value>" to resize and optimize in one step.
What is the best resize mode for JPEG XL?: Use dimensions (--resize w960) when you know the display size. Use percentage (--resize 50%) for quick scaling. Use target file size (--resize 150kB) for thumbnails and budgets. Resizing is usually the single biggest lever for reducing JPEG XL file size.