show nothing on using where clause in datalist

<asp:DataList ID="DataList1" runat="server" DataSourceID="SqlDataSource1">
                            <ItemTemplate>
                                id:
                                <asp:Label ID="idLabel" runat="server" Text='<%# Eval("id") %>' />
                                <br />
                                image1:
                                 <asp:Image ID="image1Label" runat="server" ImageUrl='<%# Eval("image1") %>' Height="250px"
                                Width="225px" />

                                <br />
                                FirstName:
                                <asp:Label ID="FirstNameLabel" runat="server" Text='<%# Eval("FirstName") %>' />
                                <br />
<br />
                            </ItemTemplate>
                            </asp:DataList>

                            <asp:SqlDataSource ID="SqlDataSource1" runat="server"
                                ConnectionString="<%$ ConnectionStrings:ModelsProfileConnectionString %>"
                                SelectCommand="SELECT * FROM [Pictures] WHERE ([FirstName] = @FirstName)">
                                <SelectParameters>
                                    <asp:SessionParameter Name="FirstName"  SessionField="FirstName" Type="String" />
                                </SelectParameters>
                            </asp:SqlDataSource>