OnMouseOver/Out med flere billeder

Nogen der kan få det her til at virke?

<script language="JavaScript" type="text/javascript">
function MenuOver(MenuItem,MenuParent){
document.MenuItem.src = "Img/'+MenuItem+'.gif"
document.MenuParent.src = "Img/MMenuLeft.gif"
}
function MenuOut(MenuItem,MenuParent){
document.MenuItem.src = "Img/'+MenuItem+'.gif"
document.MenuParent.src = "Img/MMenu.gif"
}
</script>

<a href="index.htm">
<img name="Home" border="0" src="Img/Home.gif" width="63" height="17" OnMouseOver="MenuOver('Home','Mmenu1')" OnMouseOut="MenuOut('Home','Mmenu1')">
</a>
<img name="Mmenu1" border="0" src="Img/MMenu.gif" width="18" height="17">