wget can’t find url inside local file

I have an html file.
page.html:

<html>
    <body>
    <img src="https://askubuntu.com/picture.png">
    </body>
</html>

But when i run wget as follows, it doesn’t fetch the picture. Why? In the moment of execution, i am inside my home directory, while the page and the respective picture are inside /tmp directory.

wget -kF -i /tmp/page.html -B /tmp -A png

wget output:

No URLs found in /tmp/page.html.
Converted links in 0 files in 0 seconds.

Maybe it’s a little bit easy, but i can’t cope with it now.