Hi Anders. I’ve tried on a couple of different browsers. Take a look at this link and you’ll see a demo where there are images above the post titles:
https://www.themetalmagazine.com/news/
In this example, in the ‘Post Featured Image’ dimensions I added 300px to the height box and nothing in the width box, which rather than limiting the images to 300px in height seems to have the result of hiding the images. If I add a number to the width box while there is still an entry in the height box, the images are still hidden. But if I clear the height box and add a number to the width box, the image width is transformed appropriately and is displayed.