Recorrer Registros de Tabla MysQl con Visual C#

Despues de instalar la libreria MySQL para Visual Studio.
Se tiene una data base ventas y una tabla tutorials el cual tiene un campo imagen con el nombre de la imagen que corresponde.

Formulario

C#
using MySql.Data.MySqlClient;
namespace pryGrabar
{
    public partial class Form10 : Form
    {
        MySqlConnection conn = new MySqlConnection();
        DataSet ds = new DataSet();
        DataTable dt = new DataTable();
        int i = 0;
        public Form10()
        {
            InitializeComponent();
            carga();
        }
        private void carga()
        {
            string SQL = "select * from tutorials;";
            string cad = "server=127.0.0.1;uid=minuvasoft;pwd=4321;database=ventas";
            try
            {
                conn.ConnectionString = cad;
                conn.Open();
                MySqlDataAdapter adp = new MySqlDataAdapter(SQL, conn);
                adp.Fill(ds, "tutorials");
                dt = ds.Tables["tutorials"];
               
                btnPri.Enabled = false;
                btnAnt.Enabled = false;
                carga2();
                //MessageBox.Show(dt.Rows[3][4].ToString());
                adp.Dispose();
                conn.Close();
            }
            catch (MySqlException ex)
            {
                MessageBox.Show(ex.Message);
            }
        }
        private void carga2()
        {
            textBox1.Text = dt.Rows[i][0].ToString();
            textBox2.Text = dt.Rows[i][1].ToString();
            textBox3.Text = dt.Rows[i][2].ToString();
            textBox4.Text = dt.Rows[i][3].ToString();
            string cad2 = @"c:\tuto\";
            pictureBox1.ImageLocation = cad2 + dt.Rows[i][4].ToString();
        }
        private void btnPri_Click(object sender, EventArgs e)
        {
            i = 0;
            carga2();
            btnPri.Enabled = false;
            btnAnt.Enabled = false;
            btnSig.Enabled = true;
            btnUlti.Enabled = true;
        }
 private void btnSig_Click(object sender, EventArgs e)
        {
            i = i + 1;
            carga2();
            if (i >= dt.Rows.Count-1) { i = dt.Rows.Count-1; btnSig.Enabled = false; btnUlti.Enabled = false; }
            else
            {
                btnSig.Enabled = true; btnUlti.Enabled = true;
            }
            if (i>=1) { btnPri.Enabled = true; btnAnt.Enabled = true; }
        }
        private void btnAnt_Click(object sender, EventArgs e)
        {
            i = i - 1;
            carga2();
            if (i<=0) { btnPri.Enabled = false; btnAnt.Enabled = false; }
            else { btnPri.Enabled = true; btnAnt.Enabled = true;
                btnUlti.Enabled = true; btnSig.Enabled = true;
            }
           
        }
        private void btnUlti_Click(object sender, EventArgs e)
        {
            i = dt.Rows.Count - 1;
            carga2();
            btnSig.Enabled = false;
            btnUlti.Enabled = false;
            btnAnt.Enabled = true;
            btnPri.Enabled = true;
        }
}
}
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