Good afternoon Boerderijopvang and welcome to the Events Calendar Support forum!
Thank you for reaching out to us.
I would love to help you with this topic.
The first thing I would recommend is to make sure that each event has a Featured image (this is what displays in the list view).
If the image is still not displaying, then there is a strong chance that your theme’s customization is set up in a way that does not show images in the list view (we can work on that together if necessary)
As an alternative, you might also want to try the photo view to see how you like it.
Finally, one thing you can do is to temporarily switch back to a default WordPress theme to see if that displays the images in the list view (e.g.: twenty-fifteen).
Let me know if that helps.
Have a great day!
Geoff B.