I am creating an email template where my container has a max-width: 600px. I want to be able to upload images that are in excess of 800px wide, and the images to scale down
I used a conditional for mobile, included a div tag and had set the background image url, with defined height and width percentages and the div tag has defined boundaries. Works so much better than img tag. The condition below handles displaying images in email client other than Outlook such as Mobile Browsers, WebMail, etc. Works for image data too.
Example: