function folder_paragrapgh($content){
        return preg_replace('/<p([^>]+)?>/', '<p class="para para2">', $content);
        }
        add_filter('the_content', 'folder_paragrapgh');

<script>
    (function($) {
        // do all your $ based jquery in here.
        $(function() {
          $('p.class2').prepend('<img src="http:/sample.com/img/folder.svg" width="50" height="25" alt="">');
        });
    })(jQuery);
</script>

if( is_page_template( 'f-template.php' ) ) {

    function folder_paragrapgh($content){
        return preg_replace('/<p([^>]+)?>/', '<p class="para para2">', $content);
        }
        add_filter('the_content', 'folder_paragrapgh');
    }

    the_content();
}