Hi,
The code can be found in the file administrator/components/com_hikashop/helper/image.php :
$html = '<a title="'.$alt.'" rel="{handler: \'image\'}" target="_blank" href="'.$this->uploadFolder_url.$path.'" onclick="SqueezeBox.fromElement(this,{parse: \'rel\'});return false;" '.$optionslink.'>'.$html.'</a>';
However, if you modify the code directly you will have to reapply the modification after each update. You could use a template override instead so that you could safely update HikaShop in the future while keeping your modification:
www.hikashop.com/support/documentation/6...tation.html#override