compressing a folder with in a asp.net application

ZipFile zip= new ZipFile("MyNewZip.zip"); 
zip.AddDirectory("My Pictures", true); // AddDirectory recurses subdirectories
zip.Save(); 

if (File.Exists(szFilePath))
            {
                HttpContext.Current.Response.AddHeader("Content-Disposition", "attachment; filename=" + fInfo.Name);

                HttpContext.Current.Response.AddHeader("Content-Length", fInfo.Length.ToString());
                HttpContext.Current.Response.ContentType = "application/zip";

                HttpContext.Current.Response.TransmitFile(fInfo.FullName);

                HttpContext.Current.Response.End();
                return true;
            }