> The only downside I can think of here is that plain-text-only documents tend to defer images/figures and other non-plain-text media to external files (if they

> The only downside I can think of here is that plain-text-only documents tend to defer images/figures and other non-plain-text media to external files (if they even support such media in the first place). This means that these additional files (and their formats) need to be considered as well. Before MIME was a thing,I was possible to embed images in emails by including a block of uuencoded text in the middle of the email message (which was otherwise in plain text). I suppose that could be one option assuming the client program can render them.