| Argument | Description | 
|---|---|
| sourcePath | Images' source directory (for example: /assets/images) | 
| buildPath | Destination path (for example: /static/dist/) | 
First argument to imagemin constructor is plugin array. By default, following plugins are used: [imagemin.gifsicle(), imagemin.jpegtran(), imagemin.optipng(), imagemin.svgo()]
Second argument are options. In the above example following options are used:
{
  progressive: true,
  interlaced: true,
  svgoPlugins: [{removeUnknownsAndDefaults: false}, {cleanupIDs: false}]
}
Those are completely optional.
progressive is used by imagemin-jpegtran.
interlaced is used by imagemin-gifsicle.
removeUnknownsAndDefaults and cleanupIDs are used by imagemin-svgo.