thumbnail image in asp.net C# the page can't run.

protected void Page_Load(object sender, EventArgs e)
        {

        }

        protected string GetURL()
        {
        return"ThumbnailViewer.aspx?FilePath=" + Server.UrlEncode(@"C:\Koala_3D.jpg");
        }

<form id="form1" runat="server">

   <img src='<%#GetURL() %>'   runat="server" />
   <asp:Image ID="Image1" runat="server"  ImageUrl="<%#GetURL() %>" />

   </form>

public partial class ThumbnailViewer : System.Web.UI.Page
   {
       protected void Page_Load(object sender, EventArgs e)
       {
           if ((String.IsNullOrEmpty(Request.QueryString["X"])) ||
               (String.IsNullOrEmpty(Request.QueryString["Y"])) ||
               (String.IsNullOrEmpty(Request.QueryString["FilePath"])))
           {
               // There is missing data, so don't display anything.
               // Other options include choosing reasonable defaults
               // or returning an image with some static error text.
           }
           else
           {
               int x = Int32.Parse(Request.QueryString["X"]);
               int y = Int32.Parse(Request.QueryString["Y"]);
               string file = Request.QueryString["FilePath"];
               file = Server.MapPath(file);
               // Create the in-memory bitmap where you will draw the image.
               Bitmap image = new Bitmap(x, y);
               Graphics g = Graphics.FromImage(image);

               // Load the file data.
               System.Drawing.Image thumbnail =
               System.Drawing.Image.FromFile(file);

               // Draw the thumbnail.
               g.DrawImage(thumbnail, 0, 0, x, y);

               // Render the image.
               image.Save(Response.OutputStream, ImageFormat.Jpeg);
              // image.Save(Response.OutputStream, ImageFormat.Jpeg);
               g.Dispose();
               image.Dispose();
           }

       }
   }