public function actionImageProvider($machine, $buildToken, $imageId)
    {
        $build = $this->ensureBuild($machine, $buildToken);
    
        if ($build) {
            if (!is_numeric($imageId)) {
                throw new ForbiddenHttpException("Invalid image id input.");
            }
    
            $image = Yii::$app->storage->getImage($imageId);
            /* @var $image \luya\admin\image\Item */
            if ($image->fileExists) {
                return Yii::$app->response->sendFile($image->serverSource)->send();
            }
            
            throw new NotFoundHttpException("The requested image '".$image->serverSource."' does not exist in the storage folder.");
        }
    }