I have some concerns about the way featured images work.
I read that the recommended dimensions are 1200×675 yet when I have designed my graphics with these dimensions for the hero section, they are still compressed which reduces the image quality in the process. I have designed some featured images to be 2000×1125 (the same size as 1200×675 but upscaled for higher quality purposes) but the image is resized by the theme and reduced in quality.
Strangely some of my featured images which are not 1200×675 at all are left as they are by the theme and it does not attempt to resize the images (see here and here for examples). How can I apply this setting globally across the theme, in order to stop the theme from automatically resizing featured images?