modules/media/models/Media.php
public function renderPdf($data = [])
    {
        if (isset($data['imgTag'])) {
            $pdfPreview = Yii::$app->request->baseUrl . '/theme-assets/img/pdf-preview.jpg';

            $options = [];
            if (isset($data['width'])) $options['width'] = $data['width'];
            if (isset($data['height'])) $options['height'] = $data['height'];
            return Html::img($pdfPreview, $options);
        }

        return '/' . $this->source;
    }
public function renderPdf($data = [])
    {
        if (isset($data['imgTag'])) {
            $pdfPreview = Yii::$app->request->baseUrl . '/theme-assets/img/pdf-preview.jpg';

            $options = [];
            if (isset($data['width'])) $options['width'] = $data['width'];
            if (isset($data['height'])) $options['height'] = $data['height'];
            return Html::img($pdfPreview, $options);
        }

        return '/' . $this->source;
    }
Renders PDF File
@param array $data
@return string