gozen This is very "✉ Gmail" specific, see:
Not sure how @Kyrne want's to tackle this, but if it's something built into an email service provider, I don't think it would be in our best interest to rewrite the logic to limit the max HTML input to so little kilobytes. This wouldn't be fair to those who use email services that have a higher limit or none at all and want to have super fancy email templates.
I would suggest though that you limit your HTML size to a little under the designated limit described in those articles.
If you are using images, please resize or compress the image so that it's an appropriate size to fit both it and HTML. If you are using images as a background or gradient, I suggest that you compress the image, find a CSS3 3 hack, or choose a better solution.
This is not a bug within our extension, this is actually an intended feature, by another 3rd party service provider.
[INSERT HA HA HA GENERIC PROGRAMMING BUG JOKE REFERENCE]