<?php
            if ( is_singular() && is_category('141') && has_post_thumbnail( $post->ID )) :
                echo get_the_post_thumbnail( $post->ID, 'masthead' );
            else : ?>

        <?php $newer = new WP_Query('post_type=headers&posts_per_page=5&orderby=rand'); while ($newer->have_posts()) : $newer->the_post(); ?>

        <div>


            <?php if ( get_post_meta($post->ID, 'Link URL', true) ) : ?>

                <a href="<?php echo get_post_meta($post->ID, 'Link URL', true) ?>" rel="bookmark">
                    <?php the_post_thumbnail('masthead'); ?>
                </a>

            <?php else : ?>

                <?php the_post_thumbnail('masthead') ;?>

            <?php endif; ?>

        </div>

        <?php endwhile; ?>

    </div>

        <?php endif; ?>