image viewing in data grid view in dbms

Question

i have saved record with image of student in library management system and student_image has variable varchar(50).

but when i  tried to display in grid view also then it shows exception of "perimeter is not valid"

please suggest me solution .

error occurs in line where i used ### in code below. 

 

private void textBox1_KeyUp(object sender, KeyEventArgs e)
{


dataGridView1.Columns.Clear();
dataGridView1.Refresh();
int i = 0;
if (con.State == ConnectionState.Open)
{
con.Close();
}
con.Open();

SqlCommand cmd = con.CreateCommand();
cmd.CommandType = CommandType.Text;
cmd.CommandText = "select * from student_info where student_name like('%"+ textBox1.Text +"%') ";
cmd.ExecuteNonQuery();
DataTable dt = new DataTable();
SqlDataAdapter da = new SqlDataAdapter(cmd);
da.Fill(dt);
dataGridView1.DataSource = dt;

Bitmap img;
DataGridViewImageColumn imageCol = new DataGridViewImageColumn();
imageCol.HeaderText = "student_image";
imageCol.ImageLayout = DataGridViewImageCellLayout.Zoom;
imageCol.Width = 100;
dataGridView1.Columns.Add(imageCol);

foreach (DataRow dr in dt.Rows)
{
#### img = new Bitmap(@"..\..\" + dr["student_images"].ToString());
dataGridView1.Rows[i].Cells[8].Value = img;
dataGridView1.Rows[i].Height = 100;
i = i + 1;
}
}
}

}