Hook Photo Grid widget area after header.

functions.php

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

// Add photo grid widget area after header.
add_action( 'genesis_after_header', 'sp_photo_grid_widget' );
function sp_photo_grid_widget() {

	genesis_widget_area( 'photo-grid', array(
		'before' => '<div class="photo-grid"><div class="wrap">',
		'after'  => '</div></div>',
	) );

}