public function register()
    {
        /*
         * Register the image tag processing callback
         */
        TagProcessor::instance()->registerCallback(function($input, $preview) {
            if (!$preview) {
                return $input;
            }

            return preg_replace('|\<img src="image" alt="([0-9]+)"([^>]*)\/>|m',
                '<span class="image-placeholder" data-index="$1">
                    <span class="upload-dropzone">
                        <span class="label">Click or drop an image...</span>
                        <span class="indicator"></span>
                    </span>
                </span>',
            $input);
        });
    }