! dont use
<table style="margin-left:auto;margin-right:auto;">
  <tr>
    <th><img src="highburysquareext.jpg" alt="Highbury Square Development from Above" class="center" style="width:400px;height:267px;"></th>
    <th><img src="highburysquareint.jpg" alt="Highbury Square Development from Inside" class="center" style="width:400px;height:267px;"></th>
  </tr>
  <tr>
    <td>Highbury Square Development from Above</td>
    <td>Highbury Square Development from Inside</td>
  </tr>
</table>

<table style="margin-left:auto;margin-right:auto;">
  <tr>
    <th><img src="bucksroad1.jpg" alt="Stand at the Abandoned Buckingham Road Stadium" class="center" style="width:481px;height:247px;"></th>
  </tr>
  <tr>
    <td>Abandoned and Decaying Stand at Aylesbury's Buckingham Road</td>
  </tr>
</table>