How can I create images with a fluid layout in an e-marketing template in Portrait Dialogue's Message Designer?

When an e-marketing template should be viewable on desktops and also through multiple mail services on different mobile devices, it can be done by designing responsive designed templates.
Often customers try to achieve this by having different media queries imposed on master templates for different types of screen so different sizes of images are inserted for message-items and when a message is sent for a mobile phone then the relevant image is chosen.

Many customers prepare their responsive templates on their own, so in Portrait Dialogue 6.1 certain enhancements have been made to better support mobile devices through responsive design for emails.

In this version, functionality was added for images to give an option to remove width/height attributes of the IMG tag.

In Portrait Dialogue 6.0:
The image element's width and height attributes were automatically calculated and set when an image was chosen.

User-added image

In Portrait Dialogue 6.1:
In many email designs, image size attributes can now be cleared for better display on varying screen sizes.

User-added image
UPDATED:  April 3, 2017