Connection timeout issue while generating PDF using TCPDF

Question

If we remove <td>from below code it generate PDF(using TCPDF) else it gives error as Connection Timeout.

$curImageSrc = is_file("$image_dir/".$img['filename']) == true ? image_tag("../$image_dir/".$img['filename'], array('size'=>'200x150','align'=>'center','alt'=>$img['caption'])) : '';
        print <<<EOT
          <td width=25% $tdvalue_css>
            <div align="center">
              $curImageSrc
              <br />
              <u style="font-weight:bold">{$img['image_caption']}</u>
            </div>&nbsp;
          </td>

    EOT;

Please guide me, how we can resolve this issue? I tried using div-table structure but not working, table structure get disturbed in PDF output.