I am creating my drawings as google-drawings. "Publish"ing them produces a url which can be included in the discussion.

e.g. ![Figure](https://docs.google.com/drawings/d/e/2PACX-1vTxdNlvHJFkGTfWXBdx20Qtf6jNx1noxIv61gGqqmPkEob9NGNDAD1zChgw4H1iLaR8Ym0oqkb_C4lH/pub?w=470&h=696)