This only applies to the new campaign editor, which is currently only available on London template.
Our campaign editor allows you to choose whether the image should be made constrained by 50% for high-definition displays or not. By choosing this option you are making sure your image looks great on high-definition displays that are commonly found on mobile devices (iPhone, iPad) and latest computers (4k displays, Apple Retina displays).
How it works
Let’s say you have an image that is 600px by 400px (width x height). If you choose to not constrain it’s dimensions, it will look a bit blurry on high-definition displays, as they will have to stretch it out to 1200px by 800px (that’s how Retina displays work).
If you choose to constrain dimensions of that same image, it will be doubled-down in size and will only be 300px by 200px on your newsletter, but once displayed on high-definition displays it will look good as it will be stretched out to 600px by 400px, which is it’s original size.
If you do have an image that is at least twice the width of the newsletter template (600px or 640px if you go for edge to edge), then choosing this option is a must as your image will not be shrunken down and will look good on high-definition displays as well.
A visual representation of how it works is provided below.