phpcms后台无法上传图片

chmod -R 755 /path/to/upload/directory
chown -R www-data:www-data /path/to/upload/directory

upload_max_filesize = 2M
post_max_size = 8M

'filetype' => 'jpg|jpeg|gif|png',

<?php
if ($_FILES['file']['error'] == UPLOAD_ERR_OK) {
    $fileTmpPath = $_FILES['file']['tmp_name'];
    $fileName = $_FILES['file']['name'];
    $fileSize = $_FILES['file']['size'];
    $fileType = $_FILES['file']['type'];
    $fileNameCmps = explode(".", $fileName);
    $fileExtension = strtolower(end($fileNameCmps));

    $allowedFileExtensions = array('jpg', 'jpeg', 'gif', 'png');

    if (in_array($fileExtension, $allowedFileExtensions)) {
        if ($fileSize <= 2000000) { // 2MB
            $dest_path = '/path/to/upload/directory/' . $fileName;
            if (move_uploaded_file($fileTmpPath, $dest_path)) {
                echo 'File is successfully uploaded.';
            } else {
                echo 'There was some error moving the file to upload directory. Please make sure the upload directory is writable by web server.';
            }
        } else {
            echo 'File size is exceeding the limit of 2MB.';
        }
    } else {
        echo 'Only JPG, JPEG, GIF and PNG files are allowed.';
    }
} else {
    echo 'There is some error in the file upload. Please check the following error.<br>';
    echo 'Error:' . $_FILES['file']['error'];
}
?>