Message when creating a new topic/reply

That’ll be in the site settings rather than in the text customizer.

Just like normal markdown!

Example Image


Raw:

![APOD_daily-215|500x500](upload://oRmxj6LluCqJK1Da5xBn0CXkSpY.jpeg)

That’d need a CSS tweak, or you could use headers as @Moin shows below.