PHP上传将文件名更改为“图像”

I am trying to get the following function to retain the original file name on upload.

Right now it uploads the image and stores it in the correct folder; however, it changes the name of the file to image.png.

PHP:

class Upload {

    function upimg($file, $up = "./upload/") {
        $whitelist = array("jpg", "jpeg", "png", "gif");
        if (isset($_FILES[$file]) && $_FILES[$file]['error'] == 0) {
            $info = pathinfo($_FILES[$file]['name']);
            $extension = $info['extension'];
            list($width, $height, $type, $attr) = getimagesize($_FILES[$file]['tmp_name']);
            if (($width > 10 || $height > 10) & in_array($extension, $whitelist)) {
                $url = $file . '.' . $extension;
                move_uploaded_file($_FILES[$file]['tmp_name'], $up . $url);
                return $url;
            }
        }
    }

}

I imagine this is happening because $file isn't actually holding the original file name...not sure how to resolve this. Where did i go wrong??

You should change how you're defining $url from $url = $file . '.' . $extension; to $url = $FILES[$file]['name'];