Dziękuje za pomoc , i prosze krok po kroku wytłumaczyć

<?php $name = $_FILES["myfile"]["name"]; $type = $_FILES["myfile"]["type"]; $size = $_FILES["myfile"]["size"]; $temp = $_FILES["myfile"]["tmp_name"]; $error = $_FILES["myfile"]["error"]; if ($error > 0) else { if ($type == "image/png" || $size > 500000) //conditions for the file { } else { } } ?>