how to fix email template background that works for all and properly - html-email

I have a trouble with email template rendering in gmail account i.e I used background images in email template that are working fine on first render and forwarding too, but when i reply of the same email then background images gone, I could not sort out why this happening either a gmail limitations or something else. Sharing snaps to more clear my problem.

Related

https link showing in outlook where preview should be

One of my customers mentioned to me that the way they have out look set up, allows them to see a short email preview in the form
hello#email.com
Hi, this is a message preview
However when I email, the get a big long https string and at first they thought that the email might include a virus so were dubious about opening it.
I am keen to find a way to stop this happening.
My email displays as
me#email.com
<https://z86orge6w04.....>
I use Thunderbird to send my emails, I shouldnt think that my email client would cause this though.
Also I use an smtp relay mailersend and their details are included in the https link as you will see from the pic.
I have also used socket labs and when I send using their relay, the link is still there but changes slightly
So I think that it may be something to do with the fact I use an SMTP relay
I have noticed though that it only seems to be outlook that shows this, Gmail, thunderbird and others that I have sent testemails to do not display in this manner.
At first I thought that it was because my logo in the header contained a link to the website but I have removed the link and there is no change
The part at the top circled in yellow is what they see when I email, the bit below circled in red is what they see from everyone else
The problem is not related with Thunderbird but with MailerSend which is a transactional email service.
According to mailchimp:
Transactional emails are automated emails sent from one sender to one recipient, usually related to account activity or a commercial transaction.
The URL shown in the Outlook preview is a tracking URL. You can solve this problem by removing tracking or by asking support to MailerSend.

Mailchimp issues with custom templates and Gmail IOS client

Edit: Added code sample and edited question
I am having an issue with Mailchimp and Gmail for IOS client.
When I send a custom email template (cerberus-responsive) using Mailchimp the email arrives distorted in the Gmail for IOS client. If I send the same template through an email service like Putsmail, it arrives in Gmail for IOS just fine. I get similar results when I send the template to Litmus for testing. It looks fine in every client except Gmail for IOS. If I reply or forward, the problem seems to go away.
I have been removing sections of the code (two column, three column, background) to see what section is causing the issue, but so far I get the exact same results. I do not know a creative way to get the code unmodied from Gmail.
Has anyone else noticed this behavior or have a solution? I think it is something that Mailchimp is doing to the code. I contacted Mailchimp support, but they offer no support of custom templates and directed me to a troubleshooting document on the limitations of HTML Email.
Output sample
On the left is the expected result. On the right, the result I get with Gmail for IOS on an iPhone or in Litmus.
Code sample
Body is limited to 30000 characters so I can't post the code directly.
https://github.com/TedGoas/Cerberus/blob/main/cerberus-responsive.html

MJML-based emails getting aggressively clipped by Gmail

For the news outlet I work for, we use MJML-created templates to send out our newsletters, some of which can get pretty long. We had never run into the message clipped problem in Gmail through the several months we've been using MJML, but last week, all of our emails, even the shorter ones, are being clipped in Gmail. I've read that emails larger than 102kb are clipped, but my longest email clocks in at 60kb.
Does anyone know if something changed in the way Gmail determines what gets clipped?
I can share the code for my most recent clipped email if it helps.

Email Tracking issue incase of multiple receipents

I had recently made an email tracking system for a friend of mine (we track emails by using image tracking pixels). It is working perfectly fine, except for two cases..(we track emails by using image tracking pixel)
1. If I send a mail with tracking on, and then I open the same mail from “sent item”, it will read the image and will appear as mail has been read since the image was loaded again. And as such even though the receipent hasn’t opened the mail, system will still show it as a read mail
2. How do I track my email incase of multiple recipients? I mean how will i be able to check who has opened and who hasn’t out of the lot. I tried researching over the net, but found only few companies are doing that. Form what I could gather, they were somehow sending unique tracking out to all the recipents. Somehow they are splitting the mails when sent form gmail.

Hyperlinks are being overwritten in emails

I am sending out emails from my website using Zend_Mail and Send Grid. I have hyperlinks in the email that are being overwritten with what appears to be garbage by the time it gets to the user's inbox.
For example,
href="http://www.foo.com" is becoming href="http://email.foo.com/wf/click?upn=DSDRHSSBH2938TS".
I do not have this problem when I remove the 'http://' from the href. This is not a solution for me however, because links without 'http://' do not work in some email clients.
I checked the Zend Mail content and the links appear to be fine, so I am wondering if this is a problem with Send Grid or the email client. I have looked all over the web and have found very little information on this. I have seen some people with similar issues, but no one has been able to provide a real solution.
Has anyone seen anything like this? I'll be happy to provide more information if needed.
It looks like Send Grid is re-writing the URLs for click tracking. Try disabling this feature in your Send Grid account. https://sendgrid.com/docs/Apps/click_tracking.html