<?php
// Imagik 를 이용한 썸네일 생성
function thumbnail($filename, $source_path, $target_path, $thumb_width, $thumb_height)
{
   $thumbname = 'thumb-'.preg_replace("/\.[^\.]+$/i", "", $filename).'_'.$thumb_width.'x'.$thumb_height.'.png';

   $thumb_file = $target_path.'/'.$thumbname;
   if(is_file($thumb_file)) return $thumbname;

   $source_file = $source_path.'/'.$filename;
   if(!is_file($source_file)) return;

   $img = new Imagick($source_file);

   $img->thumbnailImage($thumb_width, $thumb_height);

   $img->setImageFormat('png');
   $img->writeImage($thumb_file);

   return $thumbname;
}

// 사용하기
$thumbname = thumbnail('원본파일명', '원본파일경로', '썸네일저장경로', '썸네일 넓이', '썸네일 높이');
if($thumbname)
{
   header('Expires: '.gmdate('D, d M Y H:i:s', time()+(60*60*24*365)).' GMT');
   header('Cache-Control: max-age='.(60*60*24*365));
   header('Pragma: public');
   header('Content-Type: image/png');

   $fp = fopen($filepath.'/'.$thumbname, 'rb');
   if (!fpassthru($fp)) fclose($fp);
}