workaround

main.js

var tab = jQuery('.tabs .tab-title a');
var uriBase = document.baseURI;
jQuery('.tabs .tab-title a img').first().attr('src', jQuery('.tabs .tab-title a img').first().attr('src').replace('_off', '_on'));
tab.mousedown(function(){
		var allImgs = jQuery('.tabs .tab-title a img');
		allImgs.each(function() {
			jQuery(this).attr('src', jQuery(this).attr('src').replace('_on', '_off'));
		});

		var classe = jQuery(this).attr('class');
		var newSrc = uriBase + 'wp-content/themes/proudmoore/assets/img/tabs-icon/' + classe + '_on.png';
		jQuery(this).find('img').attr('src', newSrc);
});