UrlHelper extension method not working

I'm trying to add an extension method to my MVC 2 project without success and after several hours of googling and looking here I'm at a loss. I've created a brand new MVC 2 project to make sure there was not anything weird about my existing project and I'm still facing the same problem. I'm sure this is a situation of I "can't see the forest for the trees" so any help would be greatly appreciated. Here is the code for the extension method.

using System.Web.Mvc;

namespace ExtensionTest.Helper
{
    public static class UrlExtensions
    {
        public static string Image(this UrlHelper helper, string fileName)
        {
            return helper.Content("~/Content/Images/" + fileName);
        }

    }
}

and here is the code in the view (standard home index view created by default for a new MVC 2 project)

<%@ Page Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage" %>
<%@ Import Namespace="ExtensionTest.Helper" %>

<asp:Content ID="Content1" ContentPlaceHolderID="TitleContent" runat="server">
    Home Page
</asp:Content>

<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">
    <%= UrlHelper.Image("test") %>
    <h2><%: ViewData["Message"] %></h2>
    <p>
        To learn more about ASP.NET MVC visit <a href="http://asp.net/mvc" title="ASP.NET MVC Website">http://asp.net/mvc</a>.
    </p>
</asp:Content>

In des开发者_JAVA技巧ign mode, when I type UrlHelper, intellisense does not show my extension method Image and if I run the project I get the following error:

CS0117: 'System.Web.Mvc.UrlHelper' does not contain a definition for 'Image'

At first I thought it was as simple as not adding a reference (Import statement), but that does not appear to be the case. The really weird thing to me is that I can add extension methods to the HtmlHelper object without issue in this same project.

Thanks in advance for any help provided.

Extension methods in .NET should be invoked on an object instance and not on the class itself (even though they are static).

So instead of:

<%= UrlHelper.Image("test") %>

try:

<%= Url.Image("test") %>