Browser Image Compression

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

Features

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

Demo / Example

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

or check the "example" folder in this repo

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:

Installing

Use as ES module:

You can install it via npm or yarn

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

import imageCompression from 'browser-image-compression';

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

(work with bundlers like webpack and rollup)

(or) Load UMD js file:

You can download imageCompression from the dist folder.

Alternatively, you can use a CDN like delivrjs:

<script type="text/javascript" src="https://cdn.jsdelivr.net/npm/browser-image-compression@2.0.2/dist/browser-image-compression.js"></script>

Support

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

(powered by Stripe)

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)
  libURL: string,               // optional, the libURL of this library for importing script in Web Worker (default: https://cdn.jsdelivr.net/npm/browser-image-compression/dist/browser-image-compression.js)
  preserveExif: boolean,        // optional, use preserve Exif metadata for JPEG image e.g., Camera model, Focal length, etc (default: false)

  signal: AbortSignal,          // optional, to abort / cancel the compression

  // 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 e.g., 'image/jpeg', 'image/png' (default: file.type)
  initialQuality: number,       // optional, initial quality value between 0 and 1 (default: 1)
  alwaysKeepResolution: boolean // optional, only reduce quality, always keep width and height (default: false)
}

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

Caveat

Each browser limits the maximum size of a browser 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.)

Abort / Cancel Compression

To use this feature, please check the browser compatibility: https://caniuse.com/?search=AbortController

function handleImageUpload(event) {

  var imageFile = event.target.files[0];

  var controller = new AbortController();

  var options = {
    // other options here
    signal: controller.signal,
  }
  imageCompression(imageFile, options)
    .then(function (compressedFile) {
      return uploadToServer(compressedFile); // write your own logic
    })
    .catch(function (error) {
      console.log(error.message); // output: I just want to stop
    });

  // simulate abort the compression after 1.5 seconds
  setTimeout(function () {
    controller.abort(new Error('I just want to stop'));
  }, 1500);
}

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
  imageCompression.copyExifWithoutOrientation(copyExifFromFile: File, copyExifToFile: File): Promise<File> // based on https://gist.github.com/tonytonyjan/ffb7cd0e82cb293b843ece7e79364233

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

IE support

This library uses ES features such as Promise API, globalThis. If you need to support browsers that do not support new ES features like IE. You can include the core-js polyfill in your project.

You can include the following script to load the core-js polyfill:

<script src="https://cdnjs.cloudflare.com/ajax/libs/core-js/3.21.1/minified.min.js"></script>

Webp support

The webp compression is supported on major browsers. Please see https://caniuse.com/mdn-api_offscreencanvas_converttoblob_option_type_parameter_webp for browser compatibility.

Remarks for compression to work in Web Worker

The browser needs to support "OffscreenCanvas" API in order to take advantage of non-blocking compression. If the browser does not support "OffscreenCanvas" API, the 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

Remarks on Content Security Policy (CSP)

If your website has CSP enabled and you want to use Web Worker (useWebWorker: true), please add the following to the response header content-security-policy: script-src 'self' blob: https://cdn.jsdelivr.net

• blob: is for loading Web Worker script
• https://cdn.jsdelivr.net is for importing this library from CDN inside Web Worker script. If you don't want to load this library from CDN, you can set your self hosted library URL in options.libURL.

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