When inspecting pages which include the WPSP displays of posts, Chrome Lighthouse returns the diagnostic that the Featured images displayed by WPSP “do not have explicit width and height“. It becomes a CLS problem.
I have set the image width and image height in the WPSP list correctly, but it does not appear in the HTML. It is the same for all the WPSP lists.
(Yet the same featured images do have explicit width and height in HTML when the post is viewed in full. Images within the wp-show-posts-entry-content do too.)
I have added in the CSS: aspect-ratio: 2/1; object-fit: contain; But it requires the original width and height in the HTML for the image too.
This is a known issue when using the image width and image height fields on the WPSP settings on the current official version. I suggest you avoid using this as this removes the width and height attribute and crops the actual image file.
Thank you for being clear and up front about this, and offering a practical work-around. As always, that is hugely valuable and makes me respect GeneratePress and your plugins even more. Now I can just deal with it.