code: function isImage (path) {
    return new Promise((resolve, reject) => {
      getMimeType(path)
        .then((type) => {
          ;(type.indexOf('image') > -1) ? resolve(true) : resolve(false)
        })
        .catch(err => reject(err))
    })
  }
docs: Determines if a file is an image
  @param {string} path - Path to a file
  @returns {Promise}