For images you might want to try https://bbpress.org/plugins/topic/allow-images/
As for the html I’m not sure I understand your question.
Plain html should work
<img src="http://image-location.jpeg" />
What about html as just link to an expternal website
I’m really afraid I cannot follow you.
Could you please elaborate a bit, please?
you can put html in code tags like
QuickD – if you type a URL, bbPress automatically converts that to a clickable link. I will type just www.google.com and below it will be a link to google with the text
It’s actually harder to have bbPress NOT make links out of URLs.
You can also explicitly set the link text like this as well, by coding the full anchor link:
GO TO GOOGLE
To achieve that, I typed this:
<a href="http://google.com/">GO TO GOOGLE</a>