Signature aleatoire

<?php

$dir_list = "sign/";


$dir = opendir($dir_list);
$a = 0;


function get_ext($fil)
{
  $fin = @strlen($fil);
  return @substr($fil,($fin-3),$fin);
}

while($f = readdir($dir))
{
  if(is_file($dir_list.$f))
  {
      $img[$a] = $dir_list.$f;
      $a++;
  }
}

$img_n = @rand(0,(count($img)-1));

@header("Pragma: no-cache");
@header("Cache-Control: no-store");

switch(@get_ext($img[$img_n]))
{
  case 'gif':
      @header("Content-Type: image/gif");
  break;
   
  case 'png':
      @header("Content-Type: image/png");
  break;
   
  case 'jpg':
      @header("Content-Type: image/jpeg");
  break;
   
}
@header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");

$pic = @file_get_contents($img[$img_n]);

if($pic)
{
  echo $pic;
}
?>