Browser Image Compression

Javascript module to be run in the web browser for image compression.

Features

• You can use this module to compress jpeg and png image by reducing resolution or storage size before uploading to application server to save bandwidth.
• Multi-thread (web worker) non-blocking compression are supported through options.

Demo / Example

open https://donaldcwl.github.io/browser-image-compression/example/basic.html

or check the "example" folder in this repo

Install

You can download imageCompression from the dist folder. Alternatively, you can install it via yarn or npm

npm install browser-image-compression --save
or
yarn add browser-image-compression

or use a CDN like delivrjs:

https://cdn.jsdelivr.net/npm/[email protected]/dist/browser-image-compression.js
or
https://cdn.jsdelivr.net/npm/browser-image-compression@latest/dist/browser-image-compression.js

How to use this module in your project?

Use as ES module

(can be used in framework like React, Angular, Vue etc)

(work with bundler like webpack and rollup)

import imageCompression from 'browser-image-compression';

or

In html file

<script type="text/javascript" src="https://cdn.jsdelivr.net/npm/[email protected]/dist/browser-image-compression.js"></script>

Usage

<input type="file" accept="image/*" onchange="handleImageUpload(event);">

async await syntax:

async function handleImageUpload(event) {

  const imageFile = event.target.files[0];
  console.log('originalFile instanceof Blob', imageFile instanceof Blob); // true
  console.log(`originalFile size ${imageFile.size / 1024 / 1024} MB`);

  const options = {
    maxSizeMB: 1,
    maxWidthOrHeight: 1920,
    useWebWorker: true
  }
  try {
    const compressedFile = await imageCompression(imageFile, options);
    console.log('compressedFile instanceof Blob', compressedFile instanceof Blob); // true
    console.log(`compressedFile size ${compressedFile.size / 1024 / 1024} MB`); // smaller than maxSizeMB

    await uploadToServer(compressedFile); // write your own logic
  } catch (error) {
    console.log(error);
  }

}

Promise.then().catch() syntax:

function handleImageUpload(event) {

  var imageFile = event.target.files[0];
  console.log('originalFile instanceof Blob', imageFile instanceof Blob); // true
  console.log(`originalFile size ${imageFile.size / 1024 / 1024} MB`);

  var options = {
    maxSizeMB: 1,
    maxWidthOrHeight: 1920,
    useWebWorker: true
  }
  imageCompression(imageFile, options)
    .then(function (compressedFile) {
      console.log('compressedFile instanceof Blob', compressedFile instanceof Blob); // true
      console.log(`compressedFile size ${compressedFile.size / 1024 / 1024} MB`); // smaller than maxSizeMB

      return uploadToServer(compressedFile); // write your own logic
    })
    .catch(function (error) {
      console.log(error.message);
    });
}

Support

If this project help you reduce time to develop, you can buy me a cup of coffee :)

API

Main function

// you should provide one of maxSizeMB, maxWidthOrHeight in the options
const options: Options = { 
  maxSizeMB: number,          // (default: Number.POSITIVE_INFINITY)
  maxWidthOrHeight: number,   // compressedFile will scale down by ratio to a point that width or height is smaller than maxWidthOrHeight (default: undefined)
                              // but, automatically reduce the size to smaller than the maximum Canvas size supported by each browser.
                              // Please check the Caveat part for details.
  onProgress: Function,       // optional, a function takes one progress argument (percentage from 0 to 100) 
  useWebWorker: boolean,      // optional, use multi-thread web worker, fallback to run in main-thread (default: true)

  // following options are for advanced users
  maxIteration: number,       // optional, max number of iteration to compress the image (default: 10)
  exifOrientation: number,    // optional, see https://stackoverflow.com/a/32490603/10395024
  fileType: string,           // optional, fileType override
  initialQuality: number      // optional, initial quality value between 0 and 1 (default: 1)
}

imageCompression(file: File, options: Options): Promise<File>

Caveat

Each browser limits the maximum size of a Canvas object.
So, we resize the image to less than the maximum size that each browser restricts.
(However, the proportion/ratio of the image remains.)

Helper function

• for advanced users only, most users won't need to use the helper functions

imageCompression.getDataUrlFromFile(file: File): Promise<base64 encoded string>
imageCompression.getFilefromDataUrl(dataUrl: string, filename: string, lastModified?: number): Promise<File>
imageCompression.loadImage(url: string): Promise<HTMLImageElement>
imageCompression.drawImageInCanvas(img: HTMLImageElement, fileType?: string): HTMLCanvasElement | OffscreenCanvas
imageCompression.drawFileInCanvas(file: File, options?: Options): Promise<[ImageBitmap | HTMLImageElement, HTMLCanvasElement | OffscreenCanvas]>
imageCompression.canvasToFile(canvas: HTMLCanvasElement | OffscreenCanvas, fileType: string, fileName: string, fileLastModified: number, quality?: number): Promise<File>
imageCompression.getExifOrientation(file: File): Promise<number> // based on https://stackoverflow.com/a/32490603/10395024

Browsers support

IE / Edge	Firefox	Chrome	Safari	iOS Safari	Opera
IE10, IE11, Edge	last 2 versions	last 2 versions	last 2 versions	last 2 versions	last 2 versions

Remarks for compression to work in Web Worker

The browser need to support "OffscreenCanvas" API in order to take advantage of non-blocking compression. If browser do not support "OffscreenCanvas" API, main thread is used instead. See https://developer.mozilla.org/en-US/docs/Web/API/OffscreenCanvas#browser_compatibility for browser compatibility of "OffscreenCanvas" API.

Typescript type definitions

Typescript definitions are included in the package & referenced in the types section of the package.json

Contribution

1. fork the repo and git clone it
2. run npm run watch # it will watch code change in lib/ folder and generate js in dist/ folder
3. add/update code in lib/ folder
4. try the code by opening example/development.html which will load the js in dist/ folder
5. add/update test in test/ folder
6. npm run test
7. push to your forked repo on github
8. make a pull request to dev branch of this repo