//设置对话框的过滤条件
            ofdSelectPic.Filter = "png文件(*.png)|*.png|jpg 文件(*.jpg)|*.jpg|所有文件(*.*)|*.*";
            ofdSelectPic.Title = "打开图片";
            ofdSelectPic.FilterIndex = 2;
            if (ofdSelectPic.ShowDialog() == DialogResult.OK)
            {
                  try
                  {
                        Bitmap bmp = new Bitmap(ofdSelectPic.FileName);//获得图片
                        Clipboard.SetDataObject(bmp, false);//将图片放在剪贴板中
                        if (rtbArticles.CanPaste(DataFormats.GetFormat(DataFormats.Bitmap)))
                            rtbArticles.Paste();//粘贴数据
                  }
                  catch (Exception)
                  {
                        MessageBox.Show("请选择正确的图片");
                  }
            }