<img src="res/img/shop-c_32.jpg" alt="" onmouseover="this.src='res/img/shop-c_29.jpg';" onmouseout="this.src='res/img/shop-c_32.jpg';">

<img src="res/img/shop-c_32.jpg" data-back="res/img/shop-c_29.jpg">

<script>

$("img[data-back]").hover(function(){

    $(this).data('fallback',$(this).attr('src'));

    $(this).attr('src',$(this).data('back'));

},function(){

    $(this).attr('src',$(this).data('fallback'));

});

</script>