dit not work path problem

no images are optimized, i'm in brunch b -p Path problem ? my images path is : app/assets/graphisam In graphisam folder there is folders and folders inside etc with a lot of images in different format (jpeg, png, png)

package.json
{
  "name": "simple-brunch",
  "version": "0.1.0",
  "private": true,
  "devDependencies": {
    "brunch": "^1.8.3",
    "javascript-brunch": "^1.7.1",
    "sass-brunch": "^1.8.10",
    "imageoptmizer-brunch": "0.0.4"
  },
  "dependencies": {
    "browser-sync-brunch": "0.0.9",
    "clean-css-brunch": "^1.7.2",
    "imageoptmizer-brunch": "0.0.6"
  }
}

brunch-config.coffe
module.exports = config:
    files:
        javascripts:
            joinTo:
                'app.js'
        stylesheets:
            joinTo:
                'styles/css/accueil.css': 'app/styles/accueil.scss'
                'styles/css/agenda.css': 'app/styles/agenda.scss'
                'styles/css/asso.css': 'app/styles/asso.scss'
                'styles/css/contacts.css': 'app/styles/contacts.scss'
                'styles/css/creations.css': 'app/styles/creations.scss'
                'styles/css/ecole.css': 'app/styles/ecole.scss'
                'styles/css/filobal.css': 'app/styles/filobal.scss'
                'styles/css/le_grenier_a_pepe.css': 'app/styles/le_grenier_a_pepe.scss'
                'styles/css/liens.css': 'app/styles/liens.scss'
                'styles/css/style.css': 'app/styles/style.scss'
    plugins:
        cleancss:
            keepSpecialComments: 0
            removeEmpty: true
            optimize: true
        imageoptmizer:
            smushit: false # if false it use jpegtran and optipng, if set to true it will use smushit
            path: 'graphisam'

steffenmllr / imageoptmizer-brunch

dit not work path problem #9