$(document).ready(function(){
  $(".choicesDiv").append("<img src='your-image-src'/>" )
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<table id="choices">
  <tr>
    <td><div class="choicesDiv" value="1"></div></td>
    <td><div class="choicesDiv" value="2"></div></td>
    <td><div class="choicesDiv" value="3"></div></td>
    <td><div class="choicesDiv" value="4"></div></td>
    <td><div class="choicesDiv" value="5"></div></td>
  </tr>
  <tr>
    <td><div class="choicesDiv" value="6"></div></td>
    <td><div class="choicesDiv" value="7"></div></td>
    <td><div class="choicesDiv" value="8"></div></td>
    <td><div class="choicesDiv" value="9"></div></td>
    <td><div class="choicesDiv" value="10"></div></td>
  </tr>
</table>