Codé rapidement, à voir si ça te convient
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" >
<meta name="geo.region" content="FR" >
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"></script>
</head>
<body>
<script type="text/javascript">
$(document).ready(function(){
var n = 1;
$(".zone .add").click(function(){
if (n < 10)
{
n++;
$('.zone ul').append('<li>Image n\''+n+'<input type="file" name="image'+n+'"></li>')
}
else
{
alert('10 images max');
}
});
return false;
});
</script>
</head>
<body>
<div class="zone">
<ul>
<li>Image n'1<input type="file" name="image1"></li>
</ul>
<a href="#" class="add">Ajouter Une image</a>
</div>
</body>
</html>