How to implement automatic image cleaning in PHP, _PHP tutorial

<&#63;php
/**
 * 图片清理计划程序，删除文件下两周没有访问的文件
 */
$sRootPath = dirname(__FILE__);
//define(TIME_LINE ,"-7 day");
//删除几天没有访问图片的时间
$dir = $sRootPath .DIRECTORY_SEPARATOR.'upload';
$iTimeLine = strtotime("-7 day");
//$iTimeLine = time();
$sHandDate = date("Ymd");
$sLogDir = dirname(__FILE__).DIRECTORY_SEPARATOR.'Imglog';
$sLog = $sLogDir.DIRECTORY_SEPARATOR.$sHandDate.'.txt';
if(!file_exists($sLogDir)) mkdir($sLogDir, 0777,true);
_clearFile($dir , $iTimeLine, $sLog);
$sEnd = 'AT'."\\t" .date("Y-m-d H:i:s")."\\t".'EXEC OVER'."\\n";
echo $sEnd;
error_log($sEnd, 3, $sLog);
/**
 * 清除文件操作，传入需要清除文件的路径
 * @param unknown_type $sPath
 */
function _clearFile($sPath, $iTimeLine, $sLog){
 if(is_dir($sPath)){
  $fp = opendir($sPath);
  while(!false == ($fn = readdir($fp))){
   if($fn == '.' || $fn =='..') continue;
   $sFilePath = $sPath.DIRECTORY_SEPARATOR.$fn;
   _clearFile($sFilePath ,$iTimeLine, $sLog);
  }
 }else{  
  if($sPath != '.' && $sPath != '..'){
  //. ..文件直接跳过，不处理
   $iLastView = fileatime($sPath);
   if($iLastView < $iTimeLine){
    if(@unlink($sPath) === true){
     //echo date("Y-m-d H:i:s").'成功删除文件'.$sPath;
     //file_put_contents($sLog,'success del file :'.$sPath."\\n", FILE_APPEND);
     //exit;
     $str =date("Y-m-d H:i:s")."\\t".'success del file :'.'['.$sPath.']'."\\n";
     error_log($str, 3, $sLog);
     //exit;
    }
   }
  }
 }
}
&#63;>