Per facilitare posto tutto il codice.
<?php


$t_stamp = (strtotime("-4 days") . "<br>");
echo date('m/d/Y') . "<br />\n";
echo date("m/d/Y",$t_stamp) . "<br />\n";


function eliminafiles($dirname){
if(file_exists($dirname) && is_file($dirname)) {
unlink($dirname);
}elseif(is_dir($dirname)){
$handle = opendir($dirname);
while (false !== ($file = readdir($handle))) {
if(is_file($dirname.$file)){
unlink($dirname.$file);
}
}
$handle = closedir($handle);
rmdir($dirname);
}
}




// echo image, date("m/d/Y",$t_stamp),"/"


function eliminafiles("image",date("m/d/Y",$t_stamp,"/"));




?>