functions.php

<?php

/**
 * Remove Featured Image from Feature Posts
 *
 * @author Bill Erickson
 * @link http://www.billerickson.net/code/remove-featured-image-from-feature-posts
 *
 */
function be_remove_image_from_features() {
  // First, we make sure we're in the grid loop.
  if( ! apply_filters( 'is_genesis_grid_loop', false ) )
		return;
		
	if( in_array( 'feature', get_post_class() ) ) {
		remove_action( 'genesis_entry_content', 'genesis_do_post_image', 8 );
		remove_action( 'genesis_post_content', 'genesis_do_post_image' );
	} else {
		add_action( 'genesis_entry_content', 'genesis_do_post_image', 8 );
		add_action( 'genesis_post_content', 'genesis_do_post_image' );
	}
}
add_action( 'genesis_before_entry', 'be_remove_image_from_features' );
add_action( 'genesis_before_post', 'be_remove_image_from_features' );