How to show image in LN using HTML

I had trouble with displaying image using html in LN. I did everything correctly, but the image did not appear. So I looked around and found that there is a special field

$DelayedImagesOK = "ok"

So when I added this field (CFD) on the form it started to worked fine.

But then I found if we click on place where the image should display (I meant on that icon) using right click and then click on show image the image would appear and field $DelayedImagesOK with value "ok" would be added.