$(function(){
    $("img.imgRo").mouseover(function(){
        $(this).attr("src",$(this).attr("src").replace(/^(.+)(\.[a-z]+)$/, "$1_ro$2"))
    }).mouseout(function(){
        $(this).attr("src",$(this).attr("src").replace(/^(.+)_ro(\.[a-z]+)$/, "$1$2"));
    }).each(function(){
        $("<img>").attr("src",$(this).attr("src").replace(/^(.+)(\.[a-z]+)$/, "$1_ro$2"))
    })
});