<script language="JavaScript1.2">
function makevisible(cur,which){
if (which==0)
cur.filters.alpha.opacity=100
else
cur.filters.alpha.opacity=20
}
</script> 



Agora, copie e cole o cdigo abaixo dentro de cada tag de imagem <img>: 

style="filter:alpha(opacity=20)" onMouseover="makevisible(this,0)" onMouseout="makevisible(this,1)" 


Se a sua imagem se chama "foto.jpg" por exemplo, a tag dever ficar :

<img src="foto.jpg" style="filter:alpha(opacity=20)" onMouseover="makevisible(this,0)" onMouseout="makevisible(this,1)"> 
