PHP - Thumbnail Script Timing Out

I have a quick question about a script I wrote that searches all .jpg images in a directory (and it's sub-directories) and makes thumbnails of them. The problem I am having is that I am getting an internal server error after about 15 seconds. I have included my script, the class it requires, and my php.ini file that resides in the root of my site. I have searched for a couple of hours online and haven't been able to come up with an answer as to why I am getting that error.

The thumbnail file...
Code: [Select]
<?php
set_time_limit(0);
require_once('classes/Create_Thumbnail.php');

$filter = '.jpg';
$directory = 'media'; // Do not include a trailing slash
$it = new RecursiveDirectoryIterator("$directory");
foreach(new RecursiveIteratorIterator($it) as $file) {
if (!((strpos(strtolower($file), $filter)) === false) || empty($filter)) {
$items[] = preg_replace("#\\\#", "/", $file);
}
}
foreach ($items as $item) {
$photo = new Create_Thumbnail($item);
$photo->createThumbnail();
}
?>

The Create_Thumbnail class...
Code: [Select]
<?php

class Create_Thumbnail
{
private $_photo;
private $_photoBasename;
private $_photoWidth;
private $_photoHeight;
private $_photoType;

private $_resizedPhoto;

private $_thumbFolder;
private $_thumbWidth  = 125;
private $_thumbHeight  = 125;
private $_thumbSuffix  = '_thumb';
private $_thumbnail;

/**
 * Constructor retrieves photo's basename, extension, width, and height.
 */
public function __construct($photo) 
{
$this->_photo  = $photo;
$this->_photoBasename  = pathinfo($this->_photo, PATHINFO_FILENAME);
$this->_extension  = pathinfo($this->_photo, PATHINFO_EXTENSION);
$this->_thumbFolder  = dirname($photo) . '/';
list($this->_photoWidth, $this->_photoHeight, $this->_photoType) = getimagesize($this->_photo);
}

/**
 * Method to resize the original image to a size that is much closer to the desired thumbnail size.
 */
public function resize() 
{
$photoRatio = $this->calculatePhotoRatio();
if ($photoRatio != 1) {
$this->_resizedWidth = round($this->_photoWidth * $photoRatio);
$this->_resizedHeight = round($this->_photoHeight * $photoRatio);
} else {
$this->_resizedWidth = $this->_thumbWidth;
$this->_resizedHeight = $this->_thumbHeight;
}
$resource = $this->createResource($this->_photoType, $this->_photo);
$resized = imagecreatetruecolor($this->_resizedWidth, $this->_resizedHeight);
imagecopyresampled($resized, $resource, 0, 0, 0, 0, $this->_resizedWidth, $this->_resizedHeight, $this->_photoWidth, $this->_photoHeight);
$this->_resizedPhoto = $this->_thumbFolder . $this->_photoBasename . '_resized.' . $this->_extension;
$this->createNewImage($this->_photoType, $resized, $this->_resizedPhoto);
imagedestroy($resource);
imagedestroy($resized);
return $this->_resizedPhoto;
}

/**
 * Method to create the thumbnail.
 */
public function createThumbnail() 
{
$source = $this->resize();
list($width_original, $height_original, $type) = getimagesize($source);
$base_name = pathinfo($source, PATHINFO_FILENAME);
$base_name = str_replace('_resized', '', $base_name);
$extension = pathinfo($source, PATHINFO_EXTENSION);
$source_x = ($width_original / 2) - ($this->_thumbWidth / 2);
$source_y = ($height_original / 2) - ($this->_thumbHeight / 2);
$resource = $this->createResource($type, $source);
$thumb = imagecreatetruecolor($this->_thumbWidth, $this->_thumbHeight);
imagecopyresampled($thumb, $resource, 0, 0, $source_x, $source_y, $this->_thumbWidth, $this->_thumbHeight, $this->_thumbWidth, $this->_thumbHeight);
$this->_thumbnail = $this->_thumbFolder . $base_name . $this->_thumbSuffix . '.' . $extension;
$this->createNewImage($type, $thumb, $this->_thumbnail);
unlink($source);
return $this->_thumbnail;
}

/**
 * Method to create an image resource.
 */
public function createResource($type, $source) 
{
switch ($type) {
case 1:
$resource = imagecreatefromgif($source);
break;
case 2:
$resource = imagecreatefromjpeg($source);
break;
case 3:
$resource = imagecreatefrompng($source);
break;
}
return $resource;
}

/**
 * Method to calculate the photo ratio.
 */
public function calculatePhotoRatio() 
{
if ($this->_photoWidth > $this->_photoHeight) {
$maximumHeight = $this->_thumbHeight;
$photoRatio = $maximumHeight / $this->_photoHeight;
} elseif ($this->_photoWidth < $this->_photoHeight) {
$maximumWidth = $this->_thumbWidth;
$photoRatio = $maximumWidth / $this->_photoWidth;
} else {
$photoRatio = 1;
}
return $photoRatio;
}

/**
 * Method to create a new image.
 */
public function createNewImage($type, $source, $destination) 
{
switch ($type) {
case 1:
if (function_exists('imagegif')) {
imagegif($source, $destination);
} else {
imagejpeg($source, $destination, 50);
}
break;
case 2:
imagejpeg($source, $destination, 100);
break;
case 3:
imagepng($source, $destination);
break;
}
}

}

The php.ini file...
Code: [Select]
file_uploads on
upload_max_filesize = 150M
post_max_size = 150M
max_input_time = -1
max_execution_time = 0
memory_limit = 150M
register_argc_argv = false