Show Featured Image for Posts and Pages if present, otherwise show responsive slider in Genesis. Details: http://sridharkatakam.com/show-featured-image-present-otherwise-show-responsive-slider-genesis/

functions.php

<?php
//* Do NOT include the opening php tag

/** Show Featured Image for Posts and Pages if present, otherwise show responsive slider */

genesis_register_sidebar( array(
  'id'				=> 'home-slider',
	'name'			=> __( 'Home Slider', 'eleven40' ),
	'description'	=> __( 'This is the after header section.', 'eleven40' ),
) );
add_action( 'genesis_after_header', 'eleven40_home_welcome_helper' );

function eleven40_home_welcome_helper() {

	if ( (is_single() || is_page()) && has_post_thumbnail() ) :
		printf( '<div %s>', genesis_attr( 'featured-image' ) );
		genesis_structural_wrap( 'featured-image' );
			genesis_image();
	    genesis_structural_wrap( 'featured-image', 'close' );
		echo '</div><!-- end #featured-image -->';

	else :

		if ( is_active_sidebar( 'home-slider' ) ) :
			printf( '<div %s>', genesis_attr( 'home-slider' ) );
			genesis_structural_wrap( 'home-slider' );
				dynamic_sidebar( 'home-slider' );
			genesis_structural_wrap( 'home-slider', 'close' );
			echo '</div><!-- end #home-slider -->';
		endif;

	endif;

}