Image Attachment page

I recently updated my website thefreshquotes.com
I cannot find the attachment php in editor.

I earlier edited the attachment page with this code

<?php if ( !empty($post->post_excerpt) ) the_excerpt(); ?>
<?php the_content(); ?>

<div class=”entry clearfix”><br/>
<?php previous_image_link( ‘thumbnail’ ); ?> ID); ?>”><?php echo wp_get_attachment_image( $post->ID, ‘medium’ ); ?>

<?php next_image_link( ‘thumbnail’ ); ?>

<p class=”nav-return”>post_parent )); ?>” title=”<?php _e(‘Return to Gallery’, ‘dynamicnewslite’); ?>” rel=”gallery”>
<?php _e(‘Return to’, ‘dynamicnewslite’); ?> <?php echo get_the_title( $post->post_parent ); ?></p>

</div>

I need to add it again, where and how to add it and how much to add.

Thank You