C# How to download all images in a document

I am in the process of creating a web browser in C# however, I cannot find a way to download all images on a certain web page to my local disk. When I navigate to my page and click on my button to download after a few seconds it says 'an exception occurred during a webclient request'. My code I am using is

 WebClient wc = new WebClient();
 HtmlElementCollection imgs = this.webBrowser1.Document.GetElementsByTagName("img");

 for (int i = 1; i < imgs.Count; i++)
 {
       wc.DownloadFile(imgs[i].GetAttribute("src"), 
            @"C:\Users\EugeneProut\Desktop\images\" + i.ToString() + ".jpg" );
 }
 wc.Dispose();

The exception I am getting as as follows

    System.Net.WebException: An exception occurred during a WebClient request.
    ---> System.NotSupportedException: The URI prefix is not recognized.
    at System.Net.WebRequest.Create(Uri requestUri, Boolean useUriBase)
    at System.Net.WebRequest.Create(Uri requestUri)
    at System.Net.WebClient.GetWebRequest(Uri address)
    at System.Net.WebClient.DownloadFile(Uri address, String fileName)
   --- End of inner exception stack trace ---

Code snippets would be best.