Feature Image – working back

I’ve recently switched from a normal one post full page.

I would like to switch over to the blog style, but have trouble with the feature image.

The first post is fine.
Additionally some of the lower feature images are not showing, and many I am adding after the posting date, and do not see them.

What can I look for to resolve this?
Image size? Something unticked

Thank you. Been using the premium version for well over a year on 5 sites.