private void dataGridView1_RowsAdded(object sender, DataGridViewRowsAddedEventArgs e)
{
  ////利用 WebClient 來下載圖片
  using (WebClient wc = new WebClient())
  {
    ////WebClient 下載完畢的響應事件綁定
    wc.DownloadDataCompleted += new DownloadDataCompletedEventHandler(wc_DownloadDataCompleted);

    ////開始異步下載，圖片URL路徑請根據(jù)實際情況自己去指定
    ////同時將DataGridView當前行的行號傳遞過去，用于指定圖片顯示的CELL
    wc.DownloadDataAsync(new Uri(this.dataGridView1.Rows[e.RowIndex].Cells[1].Value.ToString()),
      e.RowIndex);
  }
}


void wc_DownloadDataCompleted(object sender, DownloadDataCompletedEventArgs e)
{
  ////如果下載過程未發(fā)生錯誤，并且未被中途取消
  if (e.Error == null && !e.Cancelled)
  {
    ////將圖片顯示于對應的指定單元格， e.UserState 就是傳入的 e.RowIndex
    ////e.Result 就是下載結(jié)果
    this.dataGridView1.Rows[(int)e.UserState].Cells["src"].Value = e.Result;
    // this.dataGridView1.Rows[(int)e.UserState].Cells["test"].Value = GetImage("1");
  }
}