Q2APHP-PRO image stream link fix

//Open core/engine.php and replace line 1593:
//From:
$message .= '<a href="http://'.SITE_DOMAIN.'/image/'.$qa_user_link.'/'.$qa_id.'"><img src="media/images/answers/'.$qa_image.'" class="img-responsive"></a>';
//Into:
$message .= '<a href="http://'.SITE_DOMAIN.'/image/'.$qa_to_user.'/'.$qa_id.'"><img src="media/images/answers/'.$qa_image.'" class="img-responsive"></a>';