Renato Henrique Teles de Souza (WH ESTÚDIO)

I got it…

jQuery(document).ready(function() {

	jQuery('.ngg-gallery-thumbnail a').each(function() {
		jQuery(this).addClass('highslide');
	});
	
	jQuery('.ngg-gallery-thumbnail-box').each(function() {
		jQuery(this).addClass('post');
	});
	
	jQuery(".post").each(function(index) {		
		jQuery(this).find("a.highslide").each(function() {
			this.onclick = function() {
				return hs.expand(this);
			}
		});
	});

});

By the way, this solution integrates the Highslide JS with the NextGEN Gallery (https://br.ww.wp.xz.cn/plugins/nextgen-gallery/) under this AjaxLoader plugin…