How to updatepanel with image

Question

So you just need to restructure your markup a little then. You need to place imgTheatreLogo inside the update panel. The triggers are actually handled by controls outside the update panel. See this documentation for reference on exactly how the UpdatePanel works.

<?xml version="1.0" encoding="utf-8"?>
<div class="field-block button-height">
  <label for="file" class="label">
    <b>Image</b> (*.jpg)
  </label>
  <table>
    <tr>
      <td>
        <span class="input file">
          <span class="file-text"></span>
          <span class="button compact">Select file</span>
          <asp:FileUpload ID="fuMovieLogo" runat="server" CssClass="file withClearFunctions />"
        </span>
        <br />
        <small class="input-info">Max file size: 2MB</small>
        <asp:Button ID="btnPreview" runat="server" Text="Preview" onclick="btnPreview_Click" />
        <asp:Button ID="btnCancelprev" runat="server" Text="Cancel" onclick="btnCancelprev_Click"/>
      </td>
      <asp:UpdatePanel ID="UpdatePanel1" runat="server">
        <ContentTemplate>
          <td style="padding-left:10px">
            <asp:Image ID="imgTheatreLogo" runat="server" Width="130px" />
            <br />
            <asp:Label ID="lblupdatelogo" runat="server" CssClass="lbl" Visible="false" Text="FDMovieUntitled.jpg"></asp:Label>
          </td>
        </ContentTemplate>
        <Triggers>
          <asp:AsyncPostBackTrigger ControlID="btnPreview" EventName="Click" />
          <asp:AsyncPostBackTrigger ControlID="btnCancelprev" EventName="Click" />
        </Triggers>
      </asp:UpdatePanel>
    </tr>
  </table>
</div>