Hi Mark, I did some testing a while ago and these were the results:
Outlook 2016/2019 for Mac
iOS Native Mail App
Samsung Native Mail App
Outlook App Android en iOS
Not supported in:
Outlook 2007 and higher on Windows
Gmail App Android en iOS**
Browser support in Chrome, Safari and Firefox, not IE/EDGE. source: https://caniuse.com/#feat=apng
* Supported when using outlook.com account
Another great resource on this and images in email in general: https://codepen.io/M_J_Robbins/pen/PKXaGM
"During Microsoft’s Surface event earlier this week, they announced a new Outlook.com experience to help users more easily identify and interact with brand’s emails in their inbox. The Microsoft business profile experience, currently in beta, will offer customers the opportunity to become a verified business with Microsoft and receive a blue check mark icon from Outlook.com indicating as much."
Maybe this could help?
Thanks Rémi! I've found this by peeking at the html of a rendered screenshot of Outlook on Android in Litmus by opening the screenshot in a new tab and change .png to .html. Doesn't work for Outlook on iOS though.
You can try to add style="margin: 0 auto" to the outer table with a width of 640 or you can create a table with a width of 100% around the current outer table like this:
<table width="100%" border="0" cellspacing="0" cellpadding="0">
<td align="center" valign="top">
<table width="640" border="0" cellspacing="0" cellpadding="0" align="center">
This approach from Mark Robbins works as well: