Needs to add anchor tag in featured image to open in new tab

by

the_post_thumbnail() will return a full link to your image. Instead, use the_post_thumbnail_url(); to only fetch the URL:

<?php if (has_post_thumbnail()) : ?>    
    <a href="https://wordpress.stackexchange.com/questions/255872/<?php the_permalink(); ?>" title="<?php the_title_attribute(); ?>" target="_blank"><img src="<?php the_post_thumbnail_url('thumbnailnew2'); ?>" alt="<?php the_title_attribute(); ?>"/></a>

This will serve you nicely. And don’t forget the semicolons, too.

Update 1

You have an unnecessary endif; causing syntax error. replace your entire code with the following:

<?php 
    $content = get_the_content();
    $content = preg_replace('/(<)([img])(\w+)([^>]*>)/', "", $content);
    $content = apply_filters('the_content', $content);
    $content = str_replace(']]>', ']]&gt;', $content);
    echo $content;
    if (has_post_thumbnail()) { ?>    
    <a href="https://wordpress.stackexchange.com/questions/255872/<?php the_permalink(); ?>" title="<?php the_title_attribute(); ?>" target="_blank"><img src="<?php the_post_thumbnail_url('thumbnailnew2'); ?>" alt="<?php the_title_attribute(); ?>"/></a>
                        <?php wp_link_pages( array( 'before' => '<div class="page-link"><span>' . __( 'Pages:', 'parabola' ) . '</span>', 'after' => '</div>' ) ); ?>
                        </div><!-- .entry-content --> 
                        <?php }
    cryout_post_after_content_hook(); ?>