private void pictureBox1_Click(object sender, EventArgs e)        {            openFileDialog1.Filter="*.jpg|*.jpg|*.bmp|*.bmp";//设置筛选列表                DialogResult dr=openFileDialog1.ShowDialog();//显示打开文件对话框            if(dr==DialogResult.OK )            {                pictureBox1.Image=new Bitmap(openFileDialog1.FileName);//添加将要显示的图像                pictureBox1.SizeMode=PictureBoxSizeMode.StretchImage;//图像被拉伸或收缩以合适大小            }        }