[Duke]

Hi,

As I told you, you need to add 1 more image there, because the slider stretches those images to the content width, that’s why changing thumbnail size and rebuilding does not matter. If it won’t fill the content width it will look ugly, but if it’s ok for you, navigate to Customize > Additional CSS and add the following snippet:

.featured-slider-area {
  max-width: 900px !important;
}

Kind Regards