<!DOCTYPE html>
<html lang="ja-JP">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width,user-scalable=yes,initial-scale=1.0,minimum-scale=1.0,maximum-scale=1.5">
<title></title>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
<script>
$(function(){
$("img:nth-of-type(1)").click(function(){
$("img").css("border","none");
$(this).css("border","3px solid #FF0000");
});
$("img:nth-of-type(2)").click(function(){
$("img").css("border","none");
$(this).css("border","3px solid #FF0000");
});
$("img:nth-of-type(3)").click(function(){
$("img").css("border","none");
$(this).css("border","3px solid #FF0000");
});
$("img:nth-of-type(4)").click(function(){
$("img").css("border","none");
$(this).css("border","3px solid #FF0000");
});
$("img:nth-of-type(5)").click(function(){
$("img").css("border","none");
$(this).css("border","3px solid #FF0000");
});
//下の記述でも可
/*
var i = 1;
$("img").each(function(){
$("img:nth-of-type(" + i + ")").click(function(){
$("img").css("border","none");
$(this).css("border","3px solid #FF0000");
});
i++;
});
*/
});
</script>
</head>
<body>
<div>
<h2>サムネイル</h2>
<img src="img/image1.png">
<img src="img/image2.png">
<img src="img/image3.png">
<img src="img/image4.png">
<img src="img/image5.png">
</div>
</body>
</html>