Link target "_blank" ??

Hi, I’m able to make link from thumbnail to an external page. But how can I set link target=”_blank” so that it opens a new tab for that page? I have tried couple of ways to add this target but no luck. Could somebody please help. Here’s the code as it is now:

<div class="ngg-gallery-thumbnail">
               <a  href="<?php echo nggcf_get_field($image->pid, 'Link'); ?>"
               target="<?php echo nggcf_get_field($image->pid, 'Target'); ?>"
               title="<?php echo esc_attr($image->description); ?>"
               data-src="<?php echo esc_attr($storage->get_image_url($image)); ?>"
               data-thumbnail="<?php echo esc_attr($storage->get_image_url($image, 'thumb')); ?>"
               data-image-id="<?php echo esc_attr($image->{$image->id_field}); ?>"
               data-title="<?php echo esc_attr($image->alttext); ?>"
               data-description="<?php echo esc_attr(stripslashes($image->description)); ?>"
               <?php echo $effect_code ?>>
                <img
                    title="<?php echo esc_attr($image->alttext)?>"
                    alt="<?php echo esc_attr($image->alttext)?>"
                    src="<?php echo esc_attr($storage->get_image_url($image, $thumbnail_size_name, TRUE))?>"
                    width="<?php echo esc_attr($thumb_size['width'])?>"
                    height="<?php echo esc_attr($thumb_size['height'])?>"
                    style="max-width:none;"
                />
            </a>
        </div>

https://wordpress.org/plugins/nextgen-gallery-custom-fields/