Do sekce <BODY> umístěte:
<SCRIPT LANGUAGE="JavaScript">
var img1 = new Image();

function init() {
img1.src = "odkazb.jpg";
}
function highlight(img) {
document[img].src = img + "b.jpg";
}

function unhighlight(img) {
document[img].src = img + "a.jpg";
}
</SCRIPT>
</HEAD>
<BODY bgcolor="Black" text="yellow" link="Red" vlink="Blue" alink="Fuchsia" onLoad="init();">
<CENTER>
<A HREF="" onMouseOver="highlight('odkaz');" onMouseOut="unhighlight('odkaz');">
<IMG NAME="odkaz" SRC="odkaza.jpg" WIDTH=135 HEIGHT=30 BORDER=0 alt="">
</A>
</CENTER>