Hi ..
You Said you are using update panel and can able have PostBack.
Then for the ajax controls in order to have asynchronous postback add trigger in inline codeas shown.make it as per your requirements.
<asp:UpdatePanel ID ="UpdatePanel1" runat ="server" >
<ContentTemplate >
<asp:Button ID="Button1" runat="server" Text="SAVE" OnClick ="btnuploadphoto_click" />
</ContentTemplate>
<Triggers >
<asp:PostBackTrigger ControlID ="btnuploadphoto" />
</Triggers>
</asp:UpdatePanel>
I have taken a sample button inthe update panel.