Image Not visible In TCPDF

Question

here I have a Data i need it in Pdf But image not showing Below are my code i already stored data in a variable

 $signature= $_POST['signature'];

$tbl = '<table cellspacing="0" cellpadding="8" border="1">
     <tr>
            <td style="width:25%;">Photo of the Documents '.$imagessignature.'</td>
        <td style="width:25%">$photoofdoc</td>
          <td style="width:25%">Approved By-'.$signature.'<br>$final_adminremark  </td>
          <td style="width:25%;">
         <img style="height:70; width:80px;" src="https://sbfasto.com/uploads/signature/'.$signature.'" />    
         </td>
    </tr>
     </table>';
$pdf->writeHTML($tbl, true, false, false, false, '');