Display post format icon only on pages in Genesis.

functions.php

<?php

//  remove the default Genesis callbacks
remove_action( 'genesis_entry_header', 'genesis_do_post_format_image', 4 );
remove_action( 'genesis_before_post_title', 'genesis_do_post_format_image' );

add_action( 'genesis_entry_header', 'custom_genesis_do_post_format_image', 4 );
add_action( 'genesis_before_post_title', 'custom_genesis_do_post_format_image' );
/**
 * Callback for Genesis 'genesis_entry_header' or 'genesis_before_post_title' action.
 *
 * If the current post object is a page exit.  Else, display the post format icon.
 *
 * @author Ryan Meier http://www.rfmeier.net/
 * 
 * @return void
 */
function custom_genesis_do_post_format_image(){

    //  if on a page, return
    if( is_page() )
        return;

    //  call the default Gensis post format image function
    genesis_do_post_format_image();

}