[nerdponx]

The broadcasting doc is surprisingly readable and easy to follow. And the rules are surprisingly simple. The diagrams and examples are excellent. https://numpy.org/doc/stable/user/basics.broadcasting.html

After taking the time to work through that doc and ponder some real-world examples, I went from being very confused by broadcasting to employing intermediate broadcasting techniques in a matter of weeks. Writing out your array dimensions in the same style of their examples (either in a text file or on a notepad) is the key technique IMO:

  Image  (3d array): 256 x 256 x 3
  Scale  (1d array):             3
  Result (3d array): 256 x 256 x 3

And of course with practice you can do it in your head.

[remram]

Please please don't put that in your head or your notepad. This is what code comments are for!

[nerdponx]

You definitely should "annotate" arrays with their expected sizes, but if you're doing a lot of broadcasting operations it can get pretty verbose to write out those tables over and over.

That said, yes, you definitely should at least make an attempt to clarify your broadcasting logic if you want to be able to read your own scripts in a month from now, let alone write maintainable production code.