в beforeSave

        $images = Helper::getImagePath($this->text);
        if ($images && is_array($images)) {
            $this->text = $this->uploadFiles($images);
        }



    /**
     * @param string $html
     * @return array $files
     */
    public static function getImagePath($html)
    {
        $files = null;
        $html = SimpleHtmlDom::str_get_html($html);
        $images = $html->find('img');
        foreach ($images as $img) {
            $src = $img->getAttribute('src');
            if ($src) {
                $files[] = $src;
            }
        }
        return $files;
    }

    /**
     * @param array $files
     * @return string $text
     */
    public function uploadFiles($files)
    {
        $extensions = array('jpg', 'gif', 'png', 'jpeg', 'bmp', 'svg');
        $text = $this->text;
        $dir = Yii::getAlias('@storage/web');
        $name = $dir . "/articles/article{$this->id}/";
        if (!is_dir($name)) {
            mkdir($name, 0777, true);
        }
        foreach ($files as $file) {
            $fileInfo = pathinfo($file);
            if (in_array($fileInfo['extension'], $extensions)) {
                $fileName = $fileInfo['basename'];
                $imgHost = parse_url($file)['host'];
                $baseHost = parse_url(Yii::getAlias('@storageUrl'))['host'];
                if ($imgHost != $baseHost) {
                    file_put_contents("{$name}/{$fileName}", fopen($file, 'r'));
                    $text = str_replace($file, Url::to("@storageUrl/articles/article{$this->id}/{$fileName}"), $text);
                }

            }
        }
        return $text;
    }