I know this is an old thread but it was useful to me today.
I had some issues getting a DIV Image in an email template to not track links. This code worked for me:
<div class="mktoImg" id="Banner" mktoName="Banner Image" mktoImgWidth="640" mktoImgsrc="https://via.placeholder.com/640x240/ccc/000" mktoLink="#">
<a class="mktNoTrack">
<img border="0" alt="" />
</a>
</div>
Wrapping the <img> tag with the <a class="mktNoTrack"> was necessary. I tried adding mktNoTrack to the div class, but that didn't work.