PureJsImage · JPEG XL

JPEG XL encoder and decoder

Open JPEG XL, JPEG, PNG or TIFF. Encode supported native integer pixels, compare decoded output, or resize and export a display image.

These tools use the current repository build. Repository functionality may be newer than the npm release. Static lossy encoding is qualified; lossy animation remains Experimental.

Interactive workbench

Encode pixels, inspect JPEG XL, or transcode JPEG

Loading a deterministic JPEG sample…

Open

Local JPEG, JPEG XL, PNG, or TIFF

Encode pixels

Pixel encoding Effort Distance Progressive lossy output

Lower distance requests finer quantization. It is not a guaranteed perceptual score. The lossy comparison accepts supported sRGB JPEG, PNG, TIFF and JXL integer samples. Alpha stays exact.

Display resize and export

Width Height Fit Export

Previews show stored geometry with straight alpha and supported HDR tone mapping. Display export normalizes orientation. Display exports convert high-depth samples to 8-bit. Encoding uses the original decoded samples, never this bounded preview. Non-pixel metadata preservation is a separate contract.

Pixel-lossless encode preserves supported decoded samples. The exact JPEG path transfers quantized DCT coefficients and reconstruction metadata without decoding RGB first. The size requirement is off unless you select it.

Synchronized preview zoom

Source

Decoded preview

Result summary

Status: Waiting

Inspection and execution evidence

Waiting for local inspection.

Browser API

import { createImageLibrary } from 'purejsimage/browser'
import { pngCodec } from 'purejsimage/codecs/png'
import { jpegxlCodec } from 'purejsimage/codecs/jpegxl'
const images = createImageLibrary([pngCodec, jpegxlCodec])
const image = await images.open(file)
const bytes = await image.jpegxl({mode: 'lossless', effort: 1}).toUint8Array()

Color JPEG: 320 × 240 four-color pattern from web-platform-tests contributors, generated with Squoosh MozJPEG (BSD 3-Clause). Grayscale JPEG and transparent PNG: generated repository fixtures (MIT). WPT license. No camera or personal data.