Revealing Featured Images when hovering on Posts in Whitespace Pro. http://sridharkatakam.com/reveal-featured-images-hovering-posts-whitespace-pro/

functions.php

add_image_size( 'home-image', 400, 400, true );

gistfile1.php

add_action( 'genesis_entry_header', 'genesis_do_post_image', 1 );

gistfile2.php

//* Display home image (Featured Image for Posts) above .article-wrap 
add_action( 'genesis_entry_header', 'sk_featured_image', 1 );
function sk_featured_image() {

	if ( ! has_post_thumbnail() ) {
		return;
	}

	$image_args = array(
		'size' => 'home-image',
		'format' => 'url'
	);

	// Get the featured image URL
	$image = genesis_get_image( $image_args );

	printf( '<div class="home-image"><a href="%s" rel="bookmark"><img src="%s" alt="%s" /></a></div>', get_permalink(), $image, the_title_attribute( 'echo=0' ) );
}

style.css

/* Featured images on hover for Posts on front page */

.home .content .entry {
	position: relative;
}

.home-image {
	position: absolute;
	top: 0;
	left: 0;
	opacity: 0;
}

.home-image img {
	vertical-align: top;
}

.home .content .entry:hover .home-image {
	opacity: 1;
}

.site-footer .social .simple-social-icons:first-child {
	position: relative;
}

@media only screen and (max-width: 1200px) {
	.home-image {
		position: static;
		opacity: 1;
	}
}

@media only screen and (max-width: 799px) {
	.home-image {
		margin-bottom: 20px;
	}
}