Previewing a post on each network

What the preview shows

The composer's Preview section shows the post for each ticked account, with a chip for each one. An Instagram or Facebook account going to more than one place, such as a feed post and a Story, gets a chip for each.

Each preview shows the account's name and picture, the caption cut roughly where that network shows "more", links and hashtags highlighted, the media in that network's shape, any title, content warning, thread parts and first comment, and the character count against that account's own limit.

How close it is

The preview uses exactly the caption, media and options the queue will send, so it cannot show something that will not go out. Where it cuts a caption is an approximation, because no network publishes where its feed cuts one, so the screen says "about".