functions.php

/**
 * Post Image
 *
 */
function be_post_image() {

	if ( ! is_singular() && genesis_get_option( 'content_archive_thumbnail' ) ) {
		$class = in_array( 'one-third', get_post_class() ) ? 'aligncenter post-image' : 'alignnone post-image';
		$img = genesis_get_image( array( 'format' => 'html', 'size' => genesis_get_option( 'image_size' ), 'attr' => array( 'class' => $class ) ) );
		printf( '<a href="%s" title="%s">%s</a>', get_permalink(), the_title_attribute( 'echo=0' ), $img );
	}


}
add_action( 'genesis_post_content', 'be_post_image' );
remove_action( 'genesis_post_content', 'genesis_do_post_image' );