<?php
    $items = new WP_Query(array(
    'post_type' => 'portfolio',
    'posts_per_page' => -1
    ));
   while ( $items->have_posts() ) :
   $items->the_post();
   $categories = get_the_category($post->ID);
  ?>

    <?php
$src = wp_get_attachment_image_src( get_post_thumbnail_id($post->ID), array( 5600,1000 ), false, '' );
?>



<?php
if ( in_category( 'print' )) { ?>

    <a href="#port-<? the_ID(); ?>" data-toggle="modal">
    <div class="span2" id="square" style="background: url(<?php echo $src[0]; ?>); background-size:100%;  background-repeat:no-repeat; background-position:center;">
    <span>
      <h3>
        <?php the_title();?>
      </h3>
    </span>
   </div>
    </a>

<?php } else { ?>

    <div class="span2" id="square" style="background:#000;">
    <span>
      <h3>
        <?php the_title();?>
      </h3>
    </span>
   </div>

<?php } ?>