问PHP/GD -图库中的照片缩略图:随机显示

EN

<a href="resources/galleries/example.jpg"><img src="mini.php?f=example.jpg" alt="Photo" /></a>

<?php
$ratio = 150;  
$dir = './resources/galleries';  

if (!isset($_GET['f'])) { 
    header('location: index.php'); 
    exit();  
}  
else { 
    $image = $_GET['f'];
    $tableau = @getimagesize($dir.'/'.$image); 
    if ($tableau == FALSE) { 
        header('location: index.php'); 
        exit(); 
    } 
    else { 
        // if jpeg
        if ($tableau[2] == 2) { 
          $src = imagecreatefromjpeg($dir.'/'.$image); 
          if ($tableau[0] > $tableau[1]) { 
            $im = imagecreatetruecolor(round(($ratio/$tableau[1])*$tableau[0]), $ratio); 
            imagecopyresampled($im, $src, 0, 0, 0, 0, round(($ratio/$tableau[1])*$tableau[0]), $ratio, $tableau[0], $tableau[1]); 
          } 
          else { 
            $im = imagecreatetruecolor($ratio, round(($ratio/$tableau[0])*$tableau[1])); 
            imagecopyresampled($im, $src, 0, 0, 0, 0, $ratio, round($tableau[1]*($ratio/$tableau[0])), $tableau[0], $tableau[1]); 
          }
          header ("Content-type: image/jpeg"); 
          imagejpeg ($im); 
        }
        elseif ($tableau[2] == 3) { // PNG
            $src = imagecreatefrompng($dir.'/'.$image); 
            if ($tableau[0] > $tableau[1]) { 
              $im = imagecreatetruecolor(round(($ratio/$tableau[1])*$tableau[0]), $ratio);
              imagecopyresampled($im, $src, 0, 0, 0, 0, round(($ratio/$tableau[1])*$tableau[0]), $ratio, $tableau[0], $tableau[1]); 
            } 
            else { 
              $im = imagecreatetruecolor($ratio, round(($ratio/$tableau[0])*$tableau[1])); 
              imagecopyresampled($im, $src, 0, 0, 0, 0, $ratio, round($tableau[1]*($ratio/$tableau[0])), $tableau[0], $tableau[1]); 
            } 
            header ("Content-type: image/png"); 
            imagepng ($im); 
        }
    }
}  
?>