It depends.
In the perfect world, and in 2016 2017, HTML emails use "CSS media queries" and adapt to screen size.
In the real world, hammering an HTML message into a square hole (your phone's screen) can be compromise, because you (the mail app) want to avoid breaking the layout too badly (Gmail in particular seems to go too far too often).
If the image is embedded in a table which has a fixed width (and people still use HTML tables, yes it's true), Aqua Mail won't touch that table.
Feel free to send a message sample to support / at / aqua-mail / dot com.
We need either an .eml attachment, or the original exact message text as a .txt attachment. Just regular "forwarding" won't work sorry, as it can rewrite the HTML.
