When I use a template in the Outlook Plugin, the images in the email are being stretched (please see attached). I've seen this happen when forwarding an email like this. Has anyone else experienced this? The preview looks fine in the Outlook plugin too
Typically this if when the image height is ahd coded, either through the styles or through the image itself
I'm not familiar with the mention Outlook plugin, but some info on how Outlook treats images might help you Dustin.
If you set width to 100% in Outlook and the image is wider than your container (like when you use double size image for Retina) Outlook will display the image at the width of your image and ignore the container width. A common fix for this is to hard code widths and heights using the attributes. Then overriding them when needed for smaller screens etc.
As Grégoire has pointed out. It may be that both your width and height are hard coded, but there is a style/css setting somewhere that is overriding the width, but leaving the hard coded height.
The solution to this that I normally apply, which would depend on where your image is added (a container with a width) is to hard code the height and width attributes for Outlook. Then add an inline style to make them responsive (style="width:100%!important;height:auto!important;").
Joe Reitz recently had this issue, as well, and the solution was the hard-code the height and width.
Related: is this a newer Outlook issue? I've seen/heard it popping up frequently lately.