how to set server folder in web.config for file upload control in asp.net

hi all,
i am using file upload control in asp.net
i am saving data in server folder(the foolder contains in my root application folder)
so i am giving absolute path to the file upload control 
i want to give the path from web.config file
and i want to give relative path (i want store server folder not in my root application)
i am using the following code for image saving
string s = FileUpload1.PostedFile.FileName.ToString(); string filename = Path.GetFileName(FileUpload1.PostedFile.FileName); //Save images into Images folder FileUpload1.SaveAs(Server.MapPath("~\\CheckImages\\" + filename)); //Getting dbconnection from web.config connectionstring // SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["dbconnection"].ToString()); ...