php生成gif png jpeg縮略圖

$file   = JRequest::getVar( 'template_full_image', '', 'files', 'array' );//獲得傳過來的圖片
jimport('joomla.filesystem.file');
$filenameext=explode(".",$file['name']);
        $filenameextcount=count($filenameext);
        $outputfile= time().".".$filenameext[(int)$filenameextcount-1];
         $filepath = JPath::clean(JPATH_ROOT.DS.'components/com_templateshow/upload/images/'.strtolower($outputfile));
         if (!JFile::upload($file['tmp_name'], $filepath)) {     
                 JError::raiseWarning(100, JText::_('Error. Unable to upload file'));     
                 return;      
               }else{
               $types = $filenameext[(int)$filenameextcount-1];
               list($width, $height) = getimagesize($filepath);
                $thumb = JPath::clean(JPATH_ROOT.DS.'components/com_templateshow/upload/images/s_'.strtolower($outputfile));
               if('gif' == $types ){
                    $gif = imagecreatefromgif($filepath);
                      imagesavealpha($gif,true);
                    $gifc = imagecreate(156, 145);
                  imagealphablending($gifc,false);
                    imagesavealpha($gifc,true);
                    imagecopyresampled($gifc,$gif, 0, 0, 0, 0, 156, 145, $width, $height);
                    imagegif($gifc,$thumb);
               }
               if( 'jpg' ==$types || 'jpeg' ==$types ){
                    $gif = imagecreatefromjpeg($filepath);
                    $gifc = imagecreatetruecolor(156, 145);
                    imagecopyresampled($gifc,$gif, 0, 0, 0, 0, 156, 145, $width, $height);
                    imagejpeg($gifc,$thumb);
               }
               if( 'png' ==$types ){
                    $gif = imagecreatefrompng($filepath);
                    imagesavealpha($gif,true);
                    $gifc = imagecreatetruecolor(156, 145);
                    imagealphablending($gifc,false);
                    imagesavealpha($gifc,true);
                    imagecopyresampled($gifc,$gif, 0, 0, 0, 0, 156, 145, $width, $height);
                    imagepng($gifc,$thumb);
               }
                                $row->template_full_image    = strtolower($outputfile);
//縮略圖文件賦值給字段               }