image-webpack-loader/README.md

Image loader module for webpack

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# image-webpack-loader

Image loader module for webpack

> Minify PNG, JPEG, GIF, SVG and WEBP images with [imagemin](https://github.com/kevva/imagemin)

*Issues with the output should be reported on the imagemin [issue tracker](https://github.com/kevva/imagemin/issues).*

## Install

```sh
$ npm install image-webpack-loader --save-dev
```

### Install in container

#### `node:12-buster`

No additional preparations required.
All dependencies will be compiled automatically.  
**Not** recommended because of large image size (~1 GB).

#### `node:12-buster-slim`

Prepare script:

```shell script
apt-get update
apt-get install -y --no-install-recommends autoconf automake g++ libpng-dev make
```

**Recommended** container image.

#### `node:12-alpine`

Prepare script:

```shell script
apk add --no-cache autoconf automake file g++ libtool make nasm libpng-dev
```

**Not** recommended because of long build time.

#### Benchmark

| Container distro      | Pull time  | Build time  | Total time  |
| --------------------- | ---------- | ----------- | ----------- |
| `node:12-buster`      | 42 seconds | 77 seconds  | 119 seconds |
| `node:12-buster-slim` | 11 seconds | 103 seconds | 114 seconds |
| `node:12-alpine`      | 8 seconds  | 122 seconds | 130 seconds |

### libpng issues

Installing on some versions of OSX may raise errors with a [missing libpng dependency](https://github.com/tcoopman/image-webpack-loader/issues/51#issuecomment-273597313): 
```
Module build failed: Error: dyld: Library not loaded: /usr/local/opt/libpng/lib/libpng16.16.dylib
```
This can be remedied by installing the newest version of libpng with [homebrew](http://brew.sh/):

```sh
brew install libpng
```

## Usage

[Documentation: Using loaders](https://webpack.js.org/concepts/loaders/)

In your `webpack.config.js`, add the image-loader, chained after the [file-loader](https://github.com/webpack/file-loader):

```js
rules: [{
  test: /\.(gif|png|jpe?g|svg)$/i,
  use: [
    'file-loader',
    {
      loader: 'image-webpack-loader',
      options: {
        bypassOnDebug: true, // webpack@1.x
        disable: true, // webpack@2.x and newer
      },
    },
  ],
}]
```

For each optimizer you wish to configure, specify the corresponding key in options:

```js
rules: [{
  test: /\.(gif|png|jpe?g|svg)$/i,
  use: [
    'file-loader',
    {
      loader: 'image-webpack-loader',
      options: {
        mozjpeg: {
          progressive: true,
        },
        // optipng.enabled: false will disable optipng
        optipng: {
          enabled: false,
        },
        pngquant: {
          quality: [0.65, 0.90],
          speed: 4
        },
        gifsicle: {
          interlaced: false,
        },
        // the webp option will enable WEBP
        webp: {
          quality: 75
        }
      }
    },
  ],
}]
```

Comes bundled with the following optimizers, which are automatically enabled by default:

- [mozjpeg](https://github.com/imagemin/imagemin-mozjpeg) — *Compress JPEG images*
- [optipng](https://github.com/kevva/imagemin-optipng) — *Compress PNG images*
- [pngquant](https://github.com/imagemin/imagemin-pngquant) — *Compress PNG images*
- [svgo](https://github.com/kevva/imagemin-svgo) — *Compress SVG images*
- [gifsicle](https://github.com/kevva/imagemin-gifsicle) — *Compress GIF images*

And optional optimizers:

- [webp](https://github.com/imagemin/imagemin-webp) — *Compress JPG & PNG images into WEBP*

_Each optimizers can be disabled by specifying `optimizer.enabled: false`, and optional ones can be enabled by simply putting them in the options_

If you are using Webpack 1, take a look at the [old docs](http://webpack.github.io/docs/using-loaders.html) (or consider upgrading).

## Options

Loader options:

#### bypassOnDebug *(all)*

Type: `boolean`
Default: `false`

Using this, no processing is done when webpack 'debug' mode is used and the loader acts as a regular file-loader. Use this to speed up initial and, to a lesser extent, subsequent compilations while developing or using webpack-dev-server. Normal builds are processed normally, outputting optimized files.

#### disable

Type: `boolean`
Default `false`

Same functionality as **bypassOnDebug** option, but doesn't depend on webpack debug mode, which was deprecated in 2.x. Basically you want to use this option if you're running webpack@2.x or newer.

For optimizer options, an up-to-date and exhaustive list is available on each optimizer repository:

- [mozjpeg](https://github.com/imagemin/imagemin-mozjpeg#options)
- [optipng](https://github.com/kevva/imagemin-optipng#options)
- [pngquant](https://github.com/imagemin/imagemin-pngquant#options)
- [svgo](https://github.com/imagemin/imagemin-svgo#options)
- [gifsicle](https://github.com/imagemin/imagemin-gifsicle#options)
- [webp](https://github.com/imagemin/imagemin-webp#options)

## Inspiration

* [gulp-imagemin](https://github.com/sindresorhus/gulp-imagemin)
* [file-loader](https://github.com/webpack/file-loader)
* [imagemin-pngquant](https://github.com/imagemin/imagemin-pngquant)

## License

MIT (http://www.opensource.org/licenses/mit-license.php)