How to show embedded images in HTML emails?

[Sheng Yang]

I have sent you two example emails that have problem showing 
images. In
the first one, pictures are at the correct position, but there is 
a line break
before and after each picture, making it hard to read. In the 
second
one, pictures are shown at the end of the page, instead of at the
correct position. For both emails, I do not know the correct way 
to
view the whole email in an external browser. What I currently do 
is call
=notmuch-view-part= on the text/html item, which shows the it in 
an
external browser similar to what I see with mu4e, but without all 
the
cid images. I think what I need is either

1) fix cid image showing in notmuch
2) a way to open the whole email (including cid images) in an 
external browser.

I guess the second option is easier to achieve?

P.S. emacs version: 26.1.91, notmuch version: 20181208 from melpa

Sheng Yang