A bulk image resizer, in PHP

resizer.php

<?php
$new_width = '640';
$uploadFolder = "images/";
$original_directory = $uploadFolder.'originals/';


// This first loop just moves anything missing over to the originals directory
foreach (glob($uploadFolder."*") as $filename) {
	$file = explode($uploadFolder, $filename);
	$file = $file[1];
	$original_filename = $original_directory.''.$file;
	if (file_exists($original_filename)) {
		// This already exists over there,
	} else {
		rename($filename, $original_filename);
	}
}

// Then we recreate all those images as smaller jpgs
foreach (glob($original_directory."*") as $o_filename) {
	$img_info = getimagesize($o_filename);
	$o_file = explode($original_directory, $o_filename);
	$o_file = $o_file[1];
	$width = $img_info[0]; 
	$height = $img_info[1];
	if ($height < $width) {
		$ratio = $width / $height;
	} else if ($width < $height) {
		$ratio = $height / $width;
	} else if ($width == $height) {
		$ratio = 1;
	}
	
	$new_height = $new_width / $ratio;
	$filetype = mime_content_type($o_filename);
	switch($filetype) {
		case 'image/jpeg':
		case 'image/jpg':
			$img = imagecreatefromjpeg($o_filename);
			break;
		case 'image/png':
			$img = imagecreatefrompng($o_filename);
			echo $o_filename;
			break;
		case 'image/gif':
			$img = imagecreatefromgif($o_filename);
			break;
	}
	$jpgname = explode('.', $o_file);
	$jpgname_full = $jpgname[0] . '.jpg';
	$new_image = $uploadFolder.''.$jpgname_full;
	$tmp = imagecreatetruecolor($new_width, $new_height);
	imagecopyresampled($tmp, $img, 0, 0, 0, 0, $new_width, $new_height, $width, $height);
	imagejpeg($tmp, $new_image, 100);
}

?>