Примерно как то так...
<script type="text/javascript">
<!--
function viewdiv(id){
var el=document.getElementById(id);
if(el.style.display=="block"){
el.style.display="none";
} else {
el.style.display="block";
}
}
//-->
</script>
<script type="text/javascript">
<!--
function viewdiv2(id){
var el=document.getElementById(id);
if(el.style.display=="block"){
el.style.display="none";
} else {
el.style.display="block";
}
}
//-->
</script>
<script type="text/javascript">
<!--
function viewdiv3(id){
var el=document.getElementById(id);
if(el.style.display=="block"){
el.style.display="none";
} else {
el.style.display="block";
}
}
//-->
</script>
<a href="javascript:void(0);" onclick="viewdiv('mydiv');">Кукла</a>
<div id="mydiv" style="display:none;"><img src="images/model/1.png"></div>
<a href="javascript:void(0);" onclick="viewdiv2('mydiv2');">Зеленое платье</a>
<div id="mydiv2" style="display:none;"><img style="margin-top: -727px;" src="images/model/4.png"></div>
<a href="javascript:void(0);" onclick="viewdiv3('mydiv3');">Красное платье</a>
<div id="mydiv3" style="display:none;"><img style="margin-top: -745px;" src="images/model/5.png"></div>