The single product page will not opens a new page (by clicking on the thumbnails) every time with this JQuery snippet code for - WPT Plugin by CodeAstrology Team

product_table_thumbnails_target_link_change.php

<?php

function codeastrology_product_table_thumbnails_target_link_change()
{
?>
<script>
    jQuery(document).ready(function() {
      'Code by Ibrahim';
      $('a[href="https://funcolorous.co.za/product/tiles/"]').each(function() {
        $(this).attr('target', '_self');
    });
  });
</script>
<?php
}
add_action('wp_footer', 'codeastrology_product_table_thumbnails_target_link_change');
?>