I've only just noticed this in the settings, but in case you haven't noticed it either - there's a setting that will make any code tags you use in posts (for images, italics and so on) work in the editor as a preview of what you'll see in the post once you submit it. T-N-M-S had this and since I started this site, I'd wondered if it was an add-on. But it's built in.
To invoke it, go to the little menu at the top left indicated by your username, select 'Look and Feel' - and in the
Posting section, tick 'Load editor in
WYSIWYG mode by default'.