nemmo\attachments\behaviors\FileBehavior::getInitialPreview PHP Method

    public function getInitialPreview()
    {
        $initialPreview = [];
        $userTempDir = $this->getModule()->getUserDirPath();
        foreach (FileHelper::findFiles($userTempDir) as $file) {
            if (substr(FileHelper::getMimeType($file), 0, 5) === 'image') {
                $initialPreview[] = Html::img(['/attachments/file/download-temp', 'filename' => basename($file)], ['class' => 'file-preview-image']);
            } else {
                $initialPreview[] = Html::beginTag('div', ['class' => 'file-preview-other']) . Html::beginTag('h2') . Html::tag('i', '', ['class' => 'glyphicon glyphicon-file']) . Html::endTag('h2') . Html::endTag('div');
            }
        }
        foreach ($this->getFiles() as $file) {
            if (substr($file->mime, 0, 5) === 'image') {
                $initialPreview[] = Html::img($file->getUrl(), ['class' => 'file-preview-image']);
            } else {
                $initialPreview[] = Html::beginTag('div', ['class' => 'file-preview-other']) . Html::beginTag('h2') . Html::tag('i', '', ['class' => 'glyphicon glyphicon-file']) . Html::endTag('h2') . Html::endTag('div');
            }
        }
        return $initialPreview;
    }