Keith Bainbridge writes:
I seem to have cured the problem of not all images rendering. I had the switch that allowed downloading external images turned OFF.
In case it's not obvious, turning that on means the sender can get the email to "phone home" when you read it, which is useful anytime the sender's business model is selling eyeballs to advertisers (e.g. spammers, social media, google). Personally I would recommend external images off and (if possible) doing something like [right click > show this external image] when you run into a legitimate email with such an external resource. https://en.wikipedia.org/wiki/Cost_per_mille https://en.wikipedia.org/wiki/Cost_per_impression This is also why you should probably use that browser plugin to disable "like" &c buttons until you actually click on them. (I forget the plugin name - I just block facebook &c completely.)