如何将BLOB转换为图像

我有一个问题，显示这是存储在我的MySQL数据库中的图片。我不知道我是否成功存储了它但是使用这个函数将图像转换为blob文件，下面是函数:

private byte[] imageToByteArray(Image imageIn)
{
    MemoryStream ms = new MemoryStream();
    imageIn.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
    return ms.ToArray();
}

当我检查我的数据库时，它显示BLOB与蓝色高亮。现在，我想在我的图片框中显示图像。我也有一个函数转换字节数组到图像..

private Image byteArrayToImage(byte[] byteArrayIn)
{
    MemoryStream ms = new MemoryStream(byteArrayIn);
    ms.Position = 0;
    Image returnImage = Image.FromStream(ms);
    return returnImage;
}

当我运行应用程序时，它说:

ArgumentException未被保留，参数无效

我试过使用这个语法:

pictureBox1.Image = byteArrayToImage(dr["img"] as byte[]);

或者我在想我是否应该首先将BLOB转换为字节数组?然后使用该函数将字节数组转换为图像?
当我点击名称时，它应该显示信息，不幸的是，我收到了参数异常..

int i = dataGridView1.SelectedCells[0].RowIndex;
string firstname = dataGridView1.Rows[i].Cells[0].Value.ToString();
string lastname = dataGridView1.Rows[i].Cells[1].Value.ToString();
Connection connect = new Connection();
MySqlConnection mySqlConnect = new MySqlConnection(connect.connString());
mySqlConnect.Open();
string s = "SELECT * FROM tbl_contacts WHERE username = '" + label1.Text + "' and (fname = '" + firstname + "' and lname = '" + lastname + "')";
MySqlCommand mySQL = new MySqlCommand(s, mySqlConnect);
mySQL.ExecuteNonQuery();
MySqlDataReader dr = mySQL.ExecuteReader();
if (dr.HasRows)
{
    dr.Read();
    txtFname.Text = dr["fname"].ToString();
    txtLname.Text = dr["lname"].ToString();
    txtBday.Text = dr["birthday"].ToString();
    txtEmail.Text = dr["email"].ToString();
    txtMobile.Text = dr["mobile"].ToString();
    txtAddress.Text = dr["address"].ToString();
    txtNotes.Text = dr["notes"].ToString();
    pictureBox1.Image = byteArrayToImage(dr["img"] as byte[]);
}