file upload options changing

if (FileUpload1.PostedFile.ContentType.ToUpper().IndexOf("IMAGE") > -1)
       {
           System.Drawing.Image img = System.Drawing.Image.FromStream(FileUpload1.PostedFile.InputStream);
           int Width = img.Width;
           int Height = img.Height;

           if (Width > 1000 || Height > 1000 || FileUpload1.PostedFile.ContentLength > 1024 * 1024 * 200)
           {
               this.ClientScript.RegisterStartupScript(this.GetType(), "Startup",
                     "<script language='javascript'>alert('The image size is too large!');</script>");
           }
           else
           {
               if (type == "jpg" || type == "gif" || type == "bmp" || type == "JPG" || type == "GIF")
               {
                   string ImagePath = "images/";
                   string sPath = Server.MapPath(ImagePath) + dataName + fileName;
                   string imgPath = ImagePath + dataName + fileName;
                   this.FileUpload1.PostedFile.SaveAs(sPath);
                   this.ClientScript.RegisterStartupScript(this.GetType(),
                         "Startup", "<script language='javascript'>alert('Success!');</script>");
                   this.Image1.ImageUrl = imgPath;
                   this.btnSubmit.Enabled = false;
                   this.btnSubmit.Text = "Success!";
                   this.btnSubmit.Enabled = true;

               }
               else
               {
                   this.ClientScript.RegisterStartupScript(this.GetType(), "Startup",
                         "<script language='javascript'>alert('File type is not right!');</script>");
               }
           }
       }