How to have openfiledialog lik thing in headertemplate of gridview?

<asp:GridView ID="gv" runat="server" AutoGenerateColumns="False"
>
<Columns>
<asp:TemplateField HeaderText="Upload Image">

<HeaderTemplate>
<asp:LinkButton ID="lnk" runat="server" Font-Underline="false" Text="upload image"></asp:LinkButton>

</HeaderTemplate>

</asp:TemplateField>
</Columns>

</asp:GridView>


if i click this link from headertemplate ,dialog box need to open from where i should select picture and display in headertemplateitself...