Featured image not full size

Hi,

I’m having a little problem with my featured images. They don’t seem to be full size. As you can see there’s a difference in size between the images featured on the homepage vs on the post page. One example:

https://culi-sandra.nl/ –> check the post of 26 Jan
https://culi-sandra.nl/zuurkoolschotel-met-cashewnoten/

As you can see the image on the homepage is smaller than the one in the post. Already tried to delete the ‘featured image’ in WordPress but the result is still the same.

Is there a trick in Vortex to make the featured image full size?

Thanks for the help!