derived from http://www.billerickson.net/genesis-portfolio/

archive-portfolio.php

<?php
/**
 * Portfolio Archive
 */

add_filter( 'genesis_pre_get_option_site_layout', '__genesis_return_full_width_content' );

add_filter( 'post_class', 'be_portfolio_post_class' );
function be_portfolio_post_class( $classes ) {
	if ( is_main_query() ) { // conditional added so that column classes don't apply to widget
		$columns = 3;

		$column_classes = array( '', '', 'one-half', 'one-third', 'one-fourth', 'one-fifth', 'one-sixth' );
		$classes[] = $column_classes[$columns];
		global $wp_query;
		if( 0 == $wp_query->current_post || 0 == $wp_query->current_post % $columns )
			$classes[] = 'first';
	} // end of new conditional
		return $classes;
}

// Remove items from loop
remove_action( 'genesis_entry_header', 'genesis_post_info', 12 );
remove_action( 'genesis_entry_content', 'genesis_do_post_content' );
remove_action( 'genesis_entry_footer', 'genesis_entry_footer_markup_open', 5 );
remove_action( 'genesis_entry_footer', 'genesis_post_meta' );
remove_action( 'genesis_entry_footer', 'genesis_entry_footer_markup_close', 15 );

// Move Title below Image
remove_action( 'genesis_entry_header', 'genesis_entry_header_markup_open', 5 );
remove_action( 'genesis_entry_header', 'genesis_entry_header_markup_close', 15 );
remove_action( 'genesis_entry_header', 'genesis_do_post_title' );
add_action( 'genesis_entry_footer', 'genesis_entry_header_markup_open', 5 );
add_action( 'genesis_entry_footer', 'genesis_entry_header_markup_close', 15 );
add_action( 'genesis_entry_footer', 'genesis_do_post_title' );

genesis();