Enhanced Brand Content - Image Dimensions

I’m creating the images for EBC for a listing. I want to create several images - sized from 970x300 to 970x600 but any images I upload greater than 970x300 are cropped to 970x300.

There are other seller listings which have very large images - I’ve downloaded one at it is 970x600. Here’s an example - the 2nd image after the logo is 970 x 600 - https://www.amazon.co.uk/Etekcity-Precision-Technology-Measuring-Backlight/dp/B01GDW2KRE

Has anyone managed to create and display an image greater than 970x300? I wonder whether this has been changed recently to limit the maximum size?