phpcms 上传不了图片

chmod -R 755 /path/to/upload/directory

upload_max_filesize = 20M
post_max_size = 20M

<form action="upload.php" method="post" enctype="multipart/form-data">
  <input type="file" name="fileToUpload" id="fileToUpload">
  <input type="submit" value="Upload Image" name="submit">
</form>

<?php
if ($_FILES["fileToUpload"]["error"] == UPLOAD_ERR_OK) {
    $uploadOk = 1;
    $fileTmpPath = $_FILES["fileToUpload"]["tmp_name"];
    $fileName = $_FILES["fileToUpload"]["name"];
    $fileSize = $_FILES["fileToUpload"]["size"];
    $fileType = $_FILES["fileToUpload"]["type"];
    $fileNameCmps = explode(".", $fileName);
    $fileExtension = strtolower(end($fileNameCmps));

    $uploadFileDir = "/path/to/upload/directory/";
    $dest_path = $uploadFileDir . $fileName;

    if(move_uploaded_file($fileTmpPath, $dest_path)) {
        echo "File is successfully uploaded.";
    } else {
        echo "There was some error moving file to upload directory. Please make sure the upload directory is writable by web server.";
    }
} else {
    echo "There is some error in the file upload. Please check the following error.<br>";
    echo 'Error:' . $_FILES["fileToUpload"]["error"];
}
?>