protected void Search(object sender, EventArgs e)
{
  MSNSearchService service = new MSNSearchService();

  // definisce la sorgente di immagini e i campi
  SourceRequest imageSource = new SourceRequest();
  imageSource.Source = SourceType.Image;
  imageSource.ResultFields = ResultFieldMask.Image | ResultFieldMask.Url;

  SearchRequest request = new SearchRequest();
  request.AppID = "...";
  request.Requests = new SourceRequest[] { imageSource };
  request.Query = txt.Text;

  SearchResponse response = service.Search(request);
  
  if (response.Responses.Length > 0)
  {
    results.DataSource = response.Responses[0].Results;
    results.DataBind();
  }
}

SearchImages.aspx

<asp:TextBox ID="txt" runat="server" />
<asp:Button ID="btnSearch" runat="server" Text="Search" onclick="Search" />
<hr />
<asp:Repeater ID="results" runat="server">
  <ItemTemplate>
    <%# FormatResult(Eval("Url"), Eval("Title"), Eval("Image")) %>
    <%# Eval("Description") %><br />
    <span style="text-decoration: underline"><%# Eval("Url") %></span>
    <hr />
  </ItemTemplate>
</asp:Repeater>

SearchImages.aspx.cs

protected string FormatResult(object title, object url, object image)
{
  string address = (image == null) ? String.Format("{0}", url) : String.Format("{0}", title);
  
  StringBuilder html = new StringBuilder();
  
  html.AppendFormat("<a href='{0}' title='{1}'>", address, title);
  
  if (image != null)
    html.AppendFormat("<img src='{0}' alt='{1}' border='0' />", ((com.live.search.soap.Image)image).ImageURL, title);
  else
    html.AppendFormat("{0}", title);
  
  html.Append("</a><br />");

  return html.ToString();
}