SAB 7.2 MACOS - image in html do not always display

I have made a bunch of html-based books in backwater.
They are exported from Nisus to HTML.
In some cases the images in the files do display, in other cases not (most).
As far as I can see the links in the HTML file are okay, e.g.

img src=“ebv-front-introductiebijbel-images/image.jpg” alt=“image.jpg”

The name of the folder is ok and the name of the jpg is okay, but yet it does not display. I have no idea why in one case in works and in the other it does not.
???