functions.php

<?php
// Don't include the <?php, only here for styling the gist

function be_move_grid_image() {
	// First, we make sure we're in the grid loop.
	if( ! apply_filters( 'is_genesis_grid_loop', false ) )
		return;

	if( in_array( 'teasuer', get_post_class() ) ) {
		// Move image above title
		remove_action( 'genesis_entry_content', 'genesis_do_post_image', 8 );
		add_action( 'genesis_entry_header', 'genesis_do_post_image', 4 );
	}
}
add_action( 'genesis_before_entry', 'be_move_grid_image' );