<?PHP
$kepek=array("jpg", "jpeg", "png", "webp", "gif");
$konyvtar="./neko/";
$dir=opendir($konyvtar);
while($file=readdir($dir))
{
    if(is_file($konyvtar.$file))
    {
        if(in_array(pathinfo($konyvtar.$file, PATHINFO_EXTENSION), $kepek))
        {
            $fajlok[]=$file;
        }
    }
}
$feltolt=fopen("lista.txt", "w");
fwrite($feltolt, implode(PHP_EOL, $fajlok));
fclose($feltolt);
?>

<?PHP
//API
$lista=file("lista.txt");
$x=mt_rand(0, count($lista)-1);
echo '{"url": "http://www.domainnev.com/neko/'.urlencode(trim($lista[$x])).'"}';
unset($lista);