i want to retrieve image from database but one error occurred at run time parameter is not valid

private void button1_Click(object sender, EventArgs e)
{
    cm = new SqlCommand("select photo from pqr where Id='abc'", cn);
    SqlDataReader rd = cm.ExecuteReader();

    if (rd.Read())
    {
        byte[] b = (Byte[])rd["photo"];
        MemoryStream ms = new MemoryStream(b);
        pictureBox1.Image = Image.FromStream(ms);//here error is occurred parameter is not Valid
    } rd.Close();
}
}