If website owners and operators want to appear in the carousel within Google search results, they're going to need to pay close attention to the ever-evolving requirements to do so.
According to a recent change in Google's article guidelines for accelerated mobile pages (AMPs), for example, the images that appear atop the content will now need to be twice the width they were previousy recommended to be.
Google has increased the image width recommendation from 696 pixels to 1200 pixels. In addition, images should contain a minimum of 800k total pixels and be presented in aspect ratios of 16:9, 4:3, and 1:1.
It's important to mention that these guidelines refer specifically to the minimum recommendations needed to have an article featured in the AMP carousel. Not adhering to these guidelines will likely mean an article won't be featured in the top stories carousel (but does not necessarily mean the AMP page will not be indexed).