Retriving image from database to image control help me

string sd = "select Name,Id,Designation,Phone,Address,Salary,Place,Image from Employee where Id='"+n+"'";
            SqlDataAdapter mad = new SqlDataAdapter(sd, DbConnection.mCon);
            DataTable dt3 = new DataTable();
            mad.Fill(dt3);
            if (dt3.Rows.Count > 0)
            {
                nam=dt3.Rows[0][0].ToString();
                id=int.Parse(dt3.Rows[0][1].ToString());
                desig = dt3.Rows[0][2].ToString();
                pho = dt3.Rows[0][3].ToString();
                addr = dt3.Rows[0][4].ToString();
                sal =float.Parse(dt3.Rows[0][5].ToString());
                plac = dt3.Rows[0][6].ToString();
                Image1.ImageUrl = dt3.Rows[0][7].ToString();
            }

protected void Button1_Click(object sender, EventArgs e)
{
     img_upload = "~/img/" + FileUpload1.FileName;
     FileUpload1.SaveAs(MapPath(img_upload));
     Image1.ImageUrl = img_upload;
}
protected void Button2_Click(object sender, EventArgs e)
{
     string sm = "insert into Employee values('" + TextBox1.Text + "','" + TextBox2.Text + "','" + TextBox3.Text + "','" + TextBox4.Text + "','" + TextBox5.Text + "','" + TextBox6.Text + "','" + TextBox7.Text + "','"+img_upload+"')";
     SqlCommand cmdn = new SqlCommand(sm, DbConnection.mCon);
     cmdn.ExecuteNonQuery();
     Response.Write("<script>alert('Employee Details Inserted')</script>");
     TextBox1.Text = TextBox2.Text = TextBox3.Text =TextBox4.Text=TextBox5.Text=TextBox6.Text=TextBox7.Text= "";
     Image1.ImageUrl = null;
}