如何在python中将临时保存的图像上传到php

I have a php page that enabled user to upload their photos.

I wanted to write a python script that are able to download image from link (and save it into temp files) and upload it to the php.

Below is the php code (get from https://www.w3schools.com/php/php_file_upload.asp) - this php file have no problem, it is just handling user image uplaod - ():

<?php
$target_dir = "uploads/";
$target_file = $target_dir . basename($_FILES["fileToUpload"]["name"]);
$uploadOk = 1;
$imageFileType = strtolower(pathinfo($target_file,PATHINFO_EXTENSION));
// Check if image file is a actual image or fake image
if(isset($_POST["submit"])) {
    $check = getimagesize($_FILES["fileToUpload"]["tmp_name"]);
    if($check !== false) {
        echo "File is an image - " . $check["mime"] . ".";
        $uploadOk = 1;
    } else {
        echo "File is not an image.";
        $uploadOk = 0;
    }
}
// Check if file already exists
if (file_exists($target_file)) {
    echo "Sorry, file already exists.";
    $uploadOk = 0;
}
// Check file size
if ($_FILES["fileToUpload"]["size"] > 500000) {
    echo "Sorry, your file is too large.";
    $uploadOk = 0;
}
// Allow certain file formats
if($imageFileType != "jpg" && $imageFileType != "png" && $imageFileType != "jpeg"
&& $imageFileType != "gif" ) {
    echo "Sorry, only JPG, JPEG, PNG & GIF files are allowed.";
    $uploadOk = 0;
}
// Check if $uploadOk is set to 0 by an error
if ($uploadOk == 0) {
    echo "Sorry, your file was not uploaded.";
// if everything is ok, try to upload file
} else {
    if (move_uploaded_file($_FILES["fileToUpload"]["tmp_name"], $target_file)) {
        echo "The file ". basename( $_FILES["fileToUpload"]["name"]). " has been uploaded.";
    } else {
        echo "Sorry, there was an error uploading your file.";
    }
}
?>

And my python script:

import requests
import base64
import tempfile

def download_file_from_url(url):

        # Stream the image from the url
        try:
                request = requests.get(url, stream=True)
        except requests.exceptions.RequestException as e:
                # TODO: log error here
                return None

        if request.status_code != requests.codes.ok:
                # TODO: log error here
                return None

        # Create a temporary file
        lf = tempfile.NamedTemporaryFile()

        # Read the streamed image in sections
        for block in request.iter_content(1024 * 8):

                # If no more file then stop
                if not block:
                    break

                # Write image block to temporary file
                lf.write(block)


        return lf



url = "http://localhost/wlox/testwp/tryupload/processupload.php"

files = {'fileToUpload': download_file_from_url('https://cnet2.cbsistatic.com/img/hjo7_UY6ykIh_9cfttUZYaiF7V0=/770x433/2017/06/21/39c814c4-4909-43e8-aa0d-89eff3aced37/apple-macbook-12-inch-2017-01.jpg')}

r = requests.post(url, files=files)

print(r.text)

When I execute the python script, it shows

Sorry, only JPG, JPEG, PNG & GIF files are allowed.Sorry, your file was not uploaded.

Can I know why? Thanks