Your theme is adding a large amount of padding to the .single-post__featured-img--layout-1
class: 100px top and bottom, or 180px for screens wider than 1025px. Look in https://eric.frydendal.org/wp-content/themes/blockst/style.css
Try Css code
.single-post__featured-img--layout-1 {
padding: 20px 0px;
}