Ieri, oggi... invece della data

[Ranma2]

fai così

$time = time();
$today = date('d-m-y', $time);
$yesterday = date('d-m-y', $time - 86400);

$filedate = date('d-m-y', $filemtime($percorsodelfile));

if ($today == $filedate)
{
    $string = 'Oggi';
}
elseif ($yesterday == $filedate)
{
    $string = 'Ieri';
}
else
{
    $string = $filedate;
}