open link in new window

Hey diefleischerei,
Try adding this code to the end of your functions.php file in Appearance > Editor:

function open_masonry_in_new_tab(){
  ?>
  <script>
(function($){
$(document).ready(function(){
 
  $('a.av-masonry-entry').click(function(){
    window.open(this.href);
    return false;
  });
 
});
})(jQuery);
</script>
  <?php
  }
  add_action('wp_footer', 'open_masonry_in_new_tab');

Best regards,
Mike