When you publish your images to Narrative, your images will be uploaded automatically resized to 5 different image sizes to ensure your website runs fast on all screen sizes.
The images sizes that Narrative uses are:
By resizing your images to 5 different sizes we can ensure that your post loads fast on all devices and screen sizes. For example. If someone views your blog on the iPhone (with a screen size of 500 pixels wide), Narrative will deliver the image that is only 500 pixels wide. This is important because it saves precious bandwidth and therefore ensures the post loads faster than ever on the user's device.