I think that you don’t “see” the following text before your cited text:
" The advantages of the widget formulation are: "
I think it is easier to understand by looking at the two codeblocks: In the first block 2 examples with normal syntax and In the second block 3 examples with macro call widget.
You have to use de widget. In your case, something like the 2nd example of 2nd codeblock. (But you don’t have to use the same indirection in a macrocall (widget)
<$macrocall $name=“image-card” img=<> width="" align=“left” …