Interesting idea, but can you give an example of the sort of thing you have in mind? It's fairly obvious how such an approach could be useful in a mathematical philosphy forum, for example, but how do you see it applying to areas like metaphysics or epistemology? In what way would it be superior to a simple verbal reply?

Someone might need to draw a rabbit that looks like a duck and compare it with another philosopher's drawing of a duck that looks like a rabbit.

Do you mean something like that?
https://www.collaboard.app/digital-lessons-with-online-whiteboard
https://www.youtube.com/watch?v=UhpE2yaSHmk

Interesting idea, but can you give an example of the sort of thing you have in mind? It's fairly obvious how such an approach could be useful in a mathematical philosphy forum, for example, but how do you see it applying to areas like metaphysics or epistemology? In what way would it be superior to a simple verbal reply? — alan1000

Search for "Euler diagram" at https://en.wikipedia.org/wiki/Epistemology.
Perhaps something like that?

A lot of people have difficulty understanding abstract concepts. Diagrams can help.

Euler diagrams

If you have a program on your computer you need to pay and be a subscriber to upload an image to a post.

I mostly use my smartphone.

I mean like more complex venn diagrams, maybe drawing float charts for logic, or parallel lines to describe causations and sequences of events etc.

That too.

I will check that out. Is it something that can be embedded into a forum? Or just an academic tool that everyone needs to buy a membership?

Syād, a great idea OP.

"A picture is worth a thousand words" is an adage in multiple languages meaning that complex and sometimes multiple ideas can be conveyed by a single still image, which conveys its meaning or essence more effectively than a mere verbal description. — Wikipedia

Some writers extraordinaire can paint with words!

Since you got me interested --for use by myself-- I checked the Web s little more. What I found out is that whiteboard animations cost from low to high. And it's usually per month.
Animation Studio (https://animationstudio.io/special/ ) has the lowest price I found: $47 paid once
But still, I'm not sure if it is this that you are looking for.