c# HtmlAgility Pack - Unable to get image src
<p>This is the code I have. I am trying to learn how to get all the img src from a URL. But, the <strong>imgs</strong> variable in my below code is always null. What am I doing wrong, please?</p>

<pre><code>using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Net;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            HtmlAgilityPack.HtmlDocument doc = new HtmlAgilityPack.HtmlDocument();
            doc.LoadHtml("http://archive.ncsa.illinois.edu/primer.html");
            HtmlAgilityPack.HtmlNodeCollection imgs = doc.DocumentNode.SelectNodes("//img");
            if (imgs != null)
            {
                foreach (HtmlAgilityPack.HtmlNode img in imgs)
                {
                    string imgSrc = img.Attributes["src"].Value;
                }
            }
            Console.ReadKey();
        }
    }
}
</code></pre>
