How to grant asp.net access to a file , which i want to host

when i upload a file with code
 if (fuProfileImage.HasFile)         {             string ext = System.IO.Path.GetExtension(fuProfileImage.FileName).ToLower();             if (ext == ".jpg" || ext == ".jpeg" || ext == ".png" || ext == ".gif")             {                 // Session["img"] = DateTime.Now.Ticks.ToString();                 string img = RefId;                 string imgf = Server.MapPath("~/Photo") + "/" + img + ext; & ...