Besides this post at Campaign Monitor that is 3 years old ( is there any more recent findings on image map support across various email client/browser/device combinations?

I recently asked our ESP's creative team and they also stated the following:

  1. Image maps do not support ALT tags, when images aren't loaded the ALT text isn't displayed in some clients.
  2. Image map usage generally results in using large images which can cause deliverability issues and hinder download speed (especially important to mobile users).
  3. And most importantly, The iOS (iphone/ipad) doesn't scale the image map link coordinates when the image is scaled which breaks the links. Since iOS represents a large majority of email opens (iPhone + iPad = 38% via this is important.

PS -- I realize that image maps are not best practices, but I'm asking anyways because one our third party integrations only email option uses image maps. I'm trying to collect some information to push back on them to develop an alternative...