How to Make a Featured Post Carousel for WordPress

It's becoming more and more common for blogs to feature certain posts at the top of the page. In this tutorial, we're going to show you how to implement this in WordPress. We'll be using the default theme, Kubrik, as our base theme, but it should be adaptable to most themes with some modification. There's very little code and featuring posts is simple.

What we're shooting for

We're going to be modifying the Kubrik theme that comes prepackaged in WordPress to be able to feature posts at the top of the page. This tutorial has only been tested on WordPress 2.5.x but it should work on the 2.3.x series as well. We're going to assume you're using 2.5.x or above. By the end of the tutorial, you'll have something like this:

Step 1 - Creating the default image

Before we do anything, go to the themes folder of your WordPress installation (wp-content/themes/) and make a backup of the "default" folder. This is the Kubrik theme we will be editing. The backup is in case you want to revert back to the original, unmodified theme.

First, we're going to make a default image in the event no featured post image is specified. Let's keep it sweet and simple for this tutorial. Open up your preferred image editor and create a 233x130px rectangle with 10px radius rounded corners. I made the background a white to grey radial gradient and put some text on top. This is what I have:

Save the image as "no-featured-image.jpg" in the "images" folder that is inside the "default" folder.

Step 2 - Add the PHP code

Now for the code. Open the "header.php" file inside the "default" folder. At the end of the file, you will see a div block and an hr tag like this:

<div id="header">
	<div id="headerimg">
		<h1><a href="<?php echo get_option('home'); ?>/"><?php bloginfo('name'); ?></a></h1>
		<div class="description"><?php bloginfo('description'); ?></div>
	</div>
</div>
<hr />

Between the ending div tag and the hr, insert the following code:

<div id="featured">
	<ul id="carousel">
		<?php
		$featured_posts = get_posts('numberposts=3&category=1');
		
		foreach( $featured_posts as $post ) {
			$custom_image = get_post_custom_values('featured_image', $post->ID);
			$image = $custom_image[0] ? $custom_image[0] : get_bloginfo("template_directory")."/images/no-featured-image.jpg";
			printf('<li><a href="%s" title="%s"><img src="%s" alt="%s" /></a></li>', get_permalink($post->ID), $post->post_title, $image, $post->post_title);
		}
		?>
	</ul>
	<div class="clear"></div>
</div>

This code will output three images in an unordered list. Each image is a link to a featured post. We'll talk about how to configure the code after we add the CSS.

Step 3 - Style with CSS

Next we need to add some CSS styles. Open up the "style.css" file and put the following code below at the end of the file. All this does is float the list elements to the left and space them out evenly.

/* Featured Post Carousel */

#featured {
	padding: 10px 10px 0 20px;
	}

#carousel {
	list-style: none;
	margin: 0;
	padding: 0;
	}

#carousel li {
	float: left;
	padding: 0;
	margin-right: 10px;
	}

Step 4 - Understanding the code

Let's take a look at what the code we added does. Inside the container div (id="featured") we have an unordered list and some PHP code to generate list elements.

1	$featured_posts = get_posts('numberposts=3&category=<strong>1</strong>');

The first line shown above retrieves the post information using the get_posts() function and assigns the post data to the $featured_posts variable. The get_posts() function excepts a single parameter in the form of a query string similar to what you might see at the end of a URL (sans the initial question mark). The first parameter is "numberposts" which we've set to 3 for this tutorial. This parameter sets how many featured posts we will be showing. The second parameter is "category" which we've set to 1. The value of the "category" parameter should be the ID of the category you are using for your featured posts. You can find the ID of a category by going to the category management page and hovering your mouse over a category title. The status bar will show a link. The last number is the category ID.

The next line is a foreach loop that will loop through the posts we've retrieved using the get_posts() function. The first line inside the foreach loop retrieves the URL of the image using the get_post_custom_values() function and stores the URL in the $custom_image variable. The first parameter specifies the key of the custom value we're using, "featured_image". The second parameter specifies what post we're getting the value from.

1	$custom_image = get_post_custom_values('featured_image', $post->ID);

In the next line we do a quick check to see if an image was indeed specified. If no image was specified, we assign the $image variable the URL of the default image. If an image was specified, we use that.

1	$image = $custom_image[0] ? $custom_image[0] : get_bloginfo("template_directory")."/images/no-featured-image.jpg";

In the last line we actually output the list elements. Each element is an image that links to the featured post.

1	printf('<li><a href="%s" title="%s"><img src="%s" alt="%s" /></a></li>', get_permalink($post->ID), $post->post_title, $image, $post->post_title);

Step 5 - Creating Featured Posts

That's it! Now, whenever you want to feature a post, assign it to the featured category and create a custom value with a key of "featured_image" and a value of the image URL. Images should be 233x130px.

See It in Action

You can view the theme in action on our NETTUTS WordPress Demo server: