That looks like it is being displayed in a web browser on the gmail site.

Are you using Thunderbird?

of course it is, did you read what I wrote? the first 5 pictures are what I see on gmail using a web browser, I see the same thing on Samsung mail on my phone, but in Thunderbird [last 2 pictures] is what is displayed. Is this any clearer?

here's a screen shot from within thunderbird

Matt was being respectful to you. Please reply in kind. I had the same reaction. No, your post was very unclear. What would have helped was seeing your latest screenshot. While I lack Matt's knowledge, my inference is that, if you have problems with one website, maybe let it go. Some websites are malformed.

of course it is, did you read what I wrote? the first 5 pictures are what I see on gmail using a web browser, I see the same thing on Samsung mail on my phone, but in Thunderbird [last 2 pictures] is what is displayed. Is this any clearer?

I read and attempted to understand, clearly I was lost in a myriad of images that all looked much the same.

With the benefit of hindsight and the clarity your last image provided I would hazard a guess that the marketing email you are pointing to uses scripts internally for layout and feedback to the website as to which button or links, offers and features you click in the email and it also probably contains a unique id for you so if you forward the email and someone else clicks the link they can monitor who you share with and extrapolate your friends/ family.

Thunderbird does not allow scripts in the body of an email not at all. This has its basis is security. The email can not download malware to your computer and launch it without a script. You might be aware of that old wives tale about not opening suspicious email. That does not apply to Thunderbird, it does apply to mail clients that allow scripts. (Web properties like gmail, although many try and sanitize the HTML, and Microsoft mail clients being the greatest numbers of those)

This failure to run scripts has downsides for many "modern" privacy invading websites like social media and marketers that want a complete profile on their "customer" from birth to the grave. To put it bluntly their scripts do not run and often even their images don't load in the email because logging of your actions is more important than content. Many of these emails also feature iFrames which Thunderbird also does not allow for security reasons. Lots of malware has been hidden in those over the years and as they inherit security parameters from the host, but are not necessarily even visible make a great avenue for allowing malware into your system. Web browsers spend a lot of effort on containment and sandboxing of pages to only accessing that simple tab. Thunderbird as it is not a browser so just disallows them.

You could probably establish which of these reasons it was in this email based on an examination of the message source, but I think you will find it is not something that you can fix even if you can establish exactly why.

If it was email from many senders, I would be suggesting that fonts and video acceleration may play a part. But as it is from a single sender my contention, without evidence one way or the other, is their HTML is simply not compatible with Thunderbird's reduced set of HTML commands.

I would not say malformed as David suggests, but using features that are mostly unwelcome in email and not supported by Thunderbird. This link is to the mailing list provider mailchimp. It is their page suggesting things that are safe for marketers to use in emails and things to use with caution as well as things to avoid. I do not think your corespondent has read the don't list from their list manager, so you are perhaps ahead of them in being aware not all HTML is email friendly or safe. https://mailchimp.com/help/limitations-of-html-email/

thanks for your help, turns out it's a gmail thing. The message is too big for gmail, they have a 102kb max. Seems the sender is unaware of these limits.

SOLVED AS UNSOLVABLE