Griff answer is right.
HI Try this..
It might help you..
the below code does the toggle operation of two predefined sizes of the images in javascript.
if you dont need toggle, u can modify in the javascript...
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="WebApplication1.WebForm1" %>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
<script src="jquery.js.js"></script>
<script type="text/javascript">
var Resize = function (imageobject) {
if (imageobject.style.height == '50px') {
imageobject.style.height = '200px';
imageobject.style.width = '200px';
}
else {
imageobject.style.height = '50px';
imageobject.style.width = '50px';
}
}
</script>
</head>
<body>
<form id="form1" runat="server">
<asp:Image ID="Image1" onclick="Resize(this);" Style="height: 50px; width: 50px;" ImageUrl="~/images/codeproject 2nd.png" runat="server" />
</form>
</body>
</html>