- Acme Themes
#53733
acmesupports
Moderator

Dear Kathiemt,
There no other way to resize featured image. You have to manually resize the image. Recommended size is 1920×1280. But for Thumbnail you can adjust the height. Please add the given CSS code in Additional CSS.
Appearance > Customize > Additional CSS

.no-sidebar .masonry-item {
    height: 325px;
}

Best Regards!