Why can I see images when I publish pages but not posts,

When I insert a media image it shows up under preview but not when I publish if it’s a post BUT if I do the same as a page it works. If I disable all the plug ins the issue remains BUT if I switch to a different theme i.e. not Activello I can add media to posts no problem.
Can I not publish images with this theme in post under the standard format?

Hello there,

I hope you are doing well today.

You may need to clear your browser cache and reload the page then use the following plugin to clear your WordPress cache:

Best Regards,