Add Excerpt Below Portfolio Archive Thumbnails Executive Theme Genesis.php

/** Add the featured image after post title */
add_action( 'genesis_before_post_title', 'executive_portfolio_grid' );
function executive_portfolio_grid() {
	if ( has_post_thumbnail() ){
		echo '<div class="portfolio-featured-image">';
		echo '<a href="' . get_permalink() .'" title="' . the_title_attribute( 'echo=0' ) . '">';
		echo get_the_post_thumbnail($thumbnail->ID, 'portfolio' );
		echo strip_tags(the_excerpt($post- id));
		echo '</a>';
		echo '</div>';
	}
}