PHP - Paginacion

function mypicturespage(){

     // conexion de base de datos

     $conexion = Conexion::singleton_conexion();

     $SQL = 'SELECT * FROM '.SSPREFIX.'imagespost WHERE usuario = :usuario ORDER BY id DESC';

     $stn = $conexion -> prepare($SQL);

     $stn -> bindParam(':usuario', $_SESSION['ssid'] ,PDO::PARAM_INT);

     $stn -> execute();

     $rstl = $stn -> fetchAll();

     if (!empty($rstl)){

       foreach ($rstl as $key){

          if ($key['type'] == 1){

           echo '

           <a class="showthepictureitem" data-toggle="modal" data-id="'.$key['id'].'" data-target="#myModal">

             <img width="128" src="'.str_replace('normal', 'small', $key['ruta']).'" >

           </a>

           ';

          }else{

           echo '

           <a class="showthepictureitem" data-toggle="modal" data-id="'.$key['id'].'" data-target="#myModal">

             <img width="400" src="'.str_replace('normal', 'small', $key['ruta']).'" >

           </a>

           ';

          }

       }

    }

}