I’m missing something basic relating to broken link checker

Broken Link Checker finds these links in my page OK

<a href=”https://google.com”>Google/a>
<a href=”about-us”>About</a>

But does not list these in results – either as Online or 404 (even if eg the image does not exist)

1. <a href=”page04#topic”> 
2. src=”images/img-city02.jpg”

Both of the above show as blue hyperlinks in my browser when viewing source. When I click these links I get the valid full URL and the page or image opens
1. https://mydomain.com/page04#topic
2. https://mydomain.com/images/img-city02.jpg

I have tried an online link checker and it does return a broken link if eg the image is missing.

What have I misunderstood or what am I doing wrong?