require('lasso').configure({
    plugins: [
        {
            plugin: 'lasso-imagemin',
            config: {
                ... // See below for config options
            }
        },
        ...
    ]
});

require('lasso').configure({
    plugins: [
        {
            plugin: 'lasso-imagemin',
            config: {
                use: [
                    {
                        paths: ['**/*.gif'],
                        plugin: 'gifsicle',
                        options: { interlaced: true }
                    },
                    {
                        paths: ['**/*.png'],
                        plugin: 'optipng',
                        options: { optimizationLevel: 3 }
                    },
                    {
                        // Non-builtin plugins must be referenced by npm module name:
                        paths: ['**/*.webp'],
                        plugin: 'imagemin-webp', // Or: require('imagemin-webp')
                        options: {}
                    }
                ]
            }
        },
        ...
    ]
});