<!-- PRIMER PASO: Copiar dentro de HEAD -->
<style>
.shakeimage{


position:relative
}
</style>

<!-- SEGUNDO PASO: Copiar en BODY -->

<script language="JavaScript1.2">
var rector=3
var stopit=0
var a=1
function init(which){
stopit=0
shake=which
shake.style.left=0
shake.style.top=0
}
function rattleimage(){
if ((!document.all&&!document.getElementById)||stopit==1)
return
if (a==1){
shake.style.top=parseInt(shake.style.top)+rector
}
else if (a==2){
shake.style.left=parseInt(shake.style.left)+rector
}
else if (a==3){
shake.style.top=parseInt(shake.style.top)-rector
}
else{
shake.style.left=parseInt(shake.style.left)-rector
}
if (a<4)
a++
else
a=1
setTimeout("rattleimage()",50)
}
function stoprattle(which){
stopit=1
which.style.left=0
which.style.top=0
}
</script>

<!--TERCER PASO: Copiar donde vaya a ir la imagen-->

<img src="imagen.gif" class="shakeimage" onMouseover="init(this);rattleimage()" onMouseout="stoprattle(this)">