Problemas con $_FILE['']['size']

[merloper]

<?php

@ob_start("ob_gzhandler");

class _aGeneUpFotos_ extends adalMySQLConect {

public $aGeneDbFotos = '_db_fotos_usuarios';
public $aGenePrimFoto = '_db_galeria_usuarios';

function _Form_ ($IdForm) {

global $FileNoSelect, $rootSecureModeAut, $Albumcreado;

if ($_POST['strupload'] == 1):

if (substr($_FILES['file_'.$IdForm]['name'], -4, 4) == '.jpg' or substr($_FILES['file_'.$IdForm]['name'], -4, 4) == '.JPG' or substr($_FILES['file_'.$IdForm]['name'], -4, 4) == '.gif' or substr($_FILES['file_'.$IdForm]['name'], -4, 4) == '.GIF' or substr($_FILES['file_'.$IdForm]['name'], -4, 4) == '.Gif' or substr($_FILES['file_'.$IdForm]['name'], -5, 5) == '.jpeg' or substr($_FILES['file_'.$IdForm]['name'], -5, 5) == '.JPEG'):

if($_FILES['file_'.$IdForm]['size'] < 1902000) {
if (is_uploaded_file($_FILES['file_'.$IdForm]['tmp_name'])) {
if($_FILES['file_'.$IdForm]['type']=="image/gif" || $_FILES['file_'.$IdForm]['type']=="image/jpeg" || $_FILES['file_'.$IdForm]['type']=="image/pjpeg") {
copy($_FILES['file_'.$IdForm]['tmp_name'], _FILEPATH_."CVStore/SharingForder/".$CodigoGuia.$_FILES['file_'.$IdForm]['name']);

$nombre_ext = $CodigoGuia.$_FILES['file_'.$IdForm]['name'];

$file_grande = _FILEPATH_."CVStore/SharingForder/".$CodigoGuia.$_FILES['file_'.$IdForm]['name'];
$image_grande = imagecreatefromjpeg($file_grande);
$width_grande = imagesx($image_grande);
$height_grande = imagesy($image_grande);

mysql_query("insert INTO ".$this->aGeneDbFotos." (imagen, id_galeria, activar)
values ('".$nombre_ext."', '".$_POST['getidgaleria']."', '1')");

@unlink (_FILEPATH_."CVStore/SharingForder/".$directorio);

$subio = true;

header("Location: misfotos.do?alid=".$_POST['getidgaleria']."");

}
}
} else {
$UpLoadSizeAlert = true;;
}

endif;

endif; // Activar subida

endif;

}

}

$UpLoad = new _aGeneUpFotos_;

$UpLoad->_Form_(1);
$UpLoad->_Form_(2);
$UpLoad->_Form_(3);
$UpLoad->_Form_(4);

?>