*update
If you think this reference is helpful check out the live Genesis Visual Hook guide. Hover over sections for more information about the hook or default functions and even tutorials. It’s more of a complete developers guide/index of genesis.

With the release of Genesis by Studiopress, the use of hooks were introduced to their themes. Hooks are a useful piece of code that allow you to “hook” into a theme without modifying core theme files. With the ability to place code in given spots throughout a theme allows simple upgrading without having to go back through all your template files to re-add your custom code.

A look into the available hooks for Genesis in their place:

Genesis Hooks – Homepage:

Genesis Hooks – Single Post:

Genesis Hooks – Page:

Genesis Hooks – Home (Sidebar Content Sidebar):

Genesis Hooks – Home ( Content – No Sidebars):

If you have recently downloaded the latest WordPress 2.9 beta build (like I have) you will find “the_post_image” no longer works! In place you will see that lovely “Fatal Error” message above.

“Post/Page Image was too generic a name. Post/Page Thumbnail is more clear, even if you can create very large thumbnail images if you so choose.”

- WordPress trac

Below, I will be noting the changes found in the latest build, and how to now use thumbnails in a WordPress theme using 2.9′s post thumbnail function.

Adding support for the post thumbnail feature in a theme

This part has not changed. Just add the code below to your themes function.php

if ( function_exists( 'add_theme_support' ) )
	add_theme_support( 'post-thumbnails' );

So, what has changed?

the_post_image to the_post_thumbnail

old:

<?php the_post_image( 'thumbnail' ); ?>

New:

<?php the_post_thumbnail( 'thumbnail' ); ?>

<?php the_post_thumbnail( 'medium' ); ?>

<?php the_post_thumbnail( 'full' ); ?>

Checking if a post has an image

Old:

<?php
	if ( has_post_image() )
		the_post_image( 'thumbnail' );
	else
		echo '<img src="default-thumbnail.jpg" alt="Default Thumbnail" title="Default Thumbnail" />';
?>

New:

<?php
	if ( has_post_thumbnail() )
		the_post_thumbnail( 'thumbnail' );
	else
		echo '<img src="default-thumbnail.jpg" alt="Default Thumbnail" title="Default Thumbnail" />';
?>

Getting the post image ID

Old:

$image_id = get_post_image_id();

New:

$image_id = get_post_thumbnail_id();

This is a developing post…