So I looked through this article and a few others.
To be safe I would use the largest mimimum image requirement as the base, because these platforms consuming the image will clip it to work in their system.
I have created some landings pages and each one has a outstanding image, this landings are for guidance and when activating the campaign and erroneously mark the size of the featured image my image was 600 x 450px I wonder if there is a certain size for the featured images of the pages?
If you're referring to these featured images and the sizes that they are displayed on the platform consuming the request (for example facebook, twitter, etc), I would refer to said platform's documentation.
I hope this is going in the correct direction. If not a screen shot or two might help.
So I looked through this article and a few others.
To be safe I would use the largest mimimum image requirement as the base, because these platforms consuming the image will clip it to work in their system.