getImage(urlOrBlob) {
    if (typeof urlOrBlob === 'string') {
      return this.getImageByURL(urlOrBlob);
    } else {
      return this.getImageByBlob(urlOrBlob);
    }
  }
Downloads image by any URL or converts from Blob, should work also for non-CORS domains

@param {String|Blob} urlOrBlob
@returns {Promise} success(Image object), fail(error)