We’ve added an option to crop thumbnails on top and it works well on our test site (theme options > blog > Thumbnails crop positions on top). Unfortunately, it doesn’t work on yours. We believe it’s because of the “imagify” plugin. To get all to work you should regenerate thumbnails via the “Regenerate Thumbnails” plugin (Værktøjer > Regenerere miniaturebilleder). Checkbox “Spring over regenerering af eksisterende korrekte miniature størrelser (hurtigere).” must be unchecked. But as the “imagify” keeps optimized versions of your images there are no changes on the site. So you should figure out how to reoptimize these new images. Maybe you can change the optimization quality and then reoptimize.
You can try it on individual images (see screenshot).