[MlMt] Message view options HTML and plaintext

[Benny Kjær Nielsen]

1. If in Preferences -> Viewer, I select "Prefer plain text", is
there a way for individual emails I'm viewing to select to
view the HTML part/switch to the HTML version?

Yes, see “View ▸ Message Body Parts”. The keys are the same as in
Apple Mail: ⌥⌘[ and ⌥⌘]

2. Is there a way to stop HTML emails from rendering attached/inline
JPEG's etc?
(Spam showing nagging stuff, even when it's marked as spam.)

No, there's no way to prevent embedded images from being shown (since
they are already fetched). I guess it could be a general option to
display images at all, but then you would probably also want a feature
to disable it (like the answer to question 1)...

3. Maybe an option for "Don't load attachments" for specific folders
would be interesting? :-)

Ah, then I think I understand question 2 since this would implicitly
allow you to do that. This feature is on my todo, but don't expect it
soon. It would probably not be so hard to not fetch (or at least not
store) large attachments, but it's tricky to make this work well when
using features which expects the entire message to exist, for example,
if using drag'n'drop to move a message between accounts or to the
desktop. (I haven't really looked into it.)

I'll note the request for such a feature to also work at the mailbox
level.