Showing more post images accumulated

Hi there!

Merry X mas everybody :slight_smile:

I'm setting up a wordpress blog for a client right now.
He wants to be able to do the following:
- Have one or two images + a text as an excerpt on the blog home page
- when opening the detail page of the post, he wants to show even more images, but accumulated on the top.

Right now, the first thing is possible. But when viewing the detail page, the additional image (right now embedded via wysiwyg editor) is on the bottom, below the text. He wants the additional images to be right on top under the images from the excerpt.

You can view an example here:

How is that going to be possible? Can you help me?

Thanks in advance and best regards,