How to Show Image on gridview image button click event ?

Question

Hello, I want to show image in new tab when i click on particular image button in GridView. i tried some code which i mentioned below,but it didn't work for me. so help me how can i do this.

Front End Code : 

<asp:GridView ID="GridView1" runat="server" CssClass="table table-bordered table-hover" DataKeyNames="ID" OnRowCommand="GridView1_RowCommand" OnSelectedIndexChanged="GridView1_SelectedIndexChanged" EmptyDataText="No records has been added." AutoGenerateColumns="False">

                               <Columns>
                                   <asp:BoundField DataField="ID" HeaderText="ID" />



                                   <asp:TemplateField HeaderText="Photo">
                                       <ItemTemplate>
                                           <asp:ImageButton ID="imgRedirect" runat="server" Height="50px" Width="50px" ImageUrl='<%# Eval("img") %>' OnClick="imgRedirect_Click" />
                                       </ItemTemplate>
                                   </asp:TemplateField>


                               </Columns>

                           </asp:GridView>

 Backend Code :

protected void imgRedirect_Click(object sender, ImageClickEventArgs e)
   {
      int getid = Convert.ToInt32(GridView1.Rows[GridView1.SelectedIndex].Cells[0].Text);
       string imagename = string.Empty;

       con.Open();
       SqlCommand cmd = new SqlCommand("select * from AddPrescription where ID='"+ getid + "'", con);
       SqlDataReader dr = cmd.ExecuteReader();
       if (dr.Read())
       {
           imagename = dr["img"].ToString();

       }
       con.Close();
       Response.Redirect(imagename);

   }