This is unfortunately not possible in the product currently.
Don't hesitate to post this idea in the Feature Requests board.
Basically it's not possible with current versions. If talk about file-attachments.
It's possible to add as "note"-part (text-view), but not able to attach picture/file or something like that (just if copied text and add it as "note" under entry-information).
Good.. if someone else can to provide something more better about situation.
@Mikilari I moved and merged your posts in the correct board