you can keep the image in focus if you add a span tag in the imagebrowser.php and update the link for the prev/next buttons-
I added a span id of “picgallery” then added “#picgallery” on the end of the previous and next links.
Example: https://celebpond.com/?p=1579
<?php if (!defined ('ABSPATH')) die ('No direct access allowed'); ?><?php if (!empty ($image)) : ?>
<div class="ngg-imagebrowser" id="<?php echo $image->anchor ?>">
<span id="picgallery"/>
<div class="ngg-imagebrowser-nav">
<div class="back">
<a class="ngg-browser-prev" id="ngg-prev-<?php echo $image->previous_pid ?>" href="<?php echo $image->previous_image_link ?><?php echo $pid?>#picgallery">◄ <?php _e('Back', 'nggallery') ?></a>
</div>
<div class="next">
<a class="ngg-browser-next" id="ngg-next-<?php echo $image->next_pid ?>" href="<?php echo $image->next_image_link ?>#picgallery"><?php _e('Next', 'nggallery') ?> ►</a>
</div>
<div class="counter"><?php _e('Picture', 'nggallery') ?> <?php echo $image->number ?> <?php _e('of', 'nggallery')?> <?php echo $image->total ?></div>
<div class="ngg-imagebrowser-desc"><p><?php echo $image->description ?></p></div>
</div>
<p><?php echo $image->alttext ?></p>
<div class="pic"><?php echo $image->href_link ?></div>
</div>
<?php endif; ?>