 private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            if (comboBox1.Text == "Normal")
                pictureBox1.SizeMode = PictureBoxSizeMode.Normal;
            else if (comboBox1.Text == "StretchImage")
                pictureBox1.SizeMode = PictureBoxSizeMode.StretchImage;
            else if (comboBox1.Text == "AutoSize")
                pictureBox1.SizeMode = PictureBoxSizeMode.AutoSize;
            else if (comboBox1.Text == "CenterImage")
                pictureBox1.SizeMode = PictureBoxSizeMode.CenterImage;

        }
