So far I have been successful embedding Youtube videos into Trello card comments; simply by including the URL in the comment Trello picks it up and renders an embedded Youtube thumbnail.
What I would like to do is the same thing, but with a simple PNG image. I don't want to upload the image as it is a Balsamiq mockup permalink which will get updated periodically, and I want the latest version to be displayed on the Trello card.
However, pasting the image URL into the Trello card has no effect.
Am I missing somthing?