How to: Enable Featured Images in Your WordPress Theme

3rd January 2012

It has always been possible to effectively attach an associated image to an article, either by uploading to the media library and creating a query, creating a custom field or installing a plugin, it’s just been a bit of a pain in the butt and required you to handle all of the cropping yourself. Cries of relief then as WordPress 2.9 was released at the end of 2009, when this became a native function. In this and all subsequent versions you can attach a Featured Image to any post or page and pull it through into your theme with just one simple line of code, giving you a clean and standardised way to create essential elements such as thumbnail images.

Enabling Featured Image Support

Featured Image support needs to be enabled on a theme by theme basis. To do so, open or create the functions.php file in your theme’s root (wp-content/themes/your-theme-name).

To add thumbnail support for all post types, add this command somewhere after the opening <?php:

Or, to enable thumbnails for just posts:

Or, just pages:

Setting Sizes

You have two options here – box resizing and hard cropping. Box resizing shrinks an image proportionally (without distorting it), until it fits inside the box you’ve specified. The whole image will show, but to get it to fit in the box it won’t always be the same size. To set your thumbnail using box-resizing, add this command below the line you created to add theme support:

Your second option is hard cropping, where the image is cropped to match the target aspect ratio, and is then shrunk to fit in the specified dimensions exactly. You’ll get the exact size you asked for, but parts of your image may have to be cropped out to get the image to fit. To set your thumbnail using hard cropping, add this command below the line you created to add theme support:

Displaying Featured Images in the Theme

Now you can add your Featured Image, if it exists, to the loop:

You can get around the problems associated with both kinds of sizing by uploading image with the correct aspect ratio.

Creating Multiple Sizes

What if, for example, you want to display a hard cropped square thumbnail on your category pages but a box resized rectangular header image within your individual posts? The answer is simple – just specify additional custom sizes:

And pull it through into the theme:


What our customers say:

I would highly recommend Hut Six Digital for your website implementation. Jo has been fantastic to work with and has exceptional knowledge in her field. She is friendly, reliable and professional, which has resulted in our fantastic new website launch. Her training was clear and concise, and I know she will be on the end of the phone or email should I need her for a little refresh. She has enabled us to take full control of our new website, which was something other companies have been unable to offer. Excellent value for money too!

Christina Canning (SMS Alarms Ltd, Thatcham)

Jo has been personable and efficient in setting up my website. She did a great job of understanding what I wanted and providing guidance from her wealth of experience. She has explained things in a non-technical way and has been very responsive, patient and flexible in working with me. In short, Jo is great value for money and easy to work with.

Vanessa Rhone (Venus Works, Oxford)

Excellent, efficient service from Jo. Highly recommend.

Xan Rice (Journalist, Oxford)

I am not exactly a technophobe but due to previous experiences of pressing buttons that I have no business pressing I have shied away from doing thing to update or improve my site. I have called on Jo Cox’s expertise several times and she is always quick, efficient and gets you back on track whilst also calming you down. I can honestly say that there is no one else I would call on in an emergency to sort out problems with my website. I have never had a bad experience with Jo’s services or with Jo as the service provider.

Lisa Bentley (Writer, Liverpool)

Jo has been amazing. Through 1-2-1 training sessions she has helped me to make significant improvements to my website functionality. This has not only been cost effective but it also has empowered me to use the skills that I have gained to edit my website myself in the future. She has simplified what I thought would be tricky tasks. I will definitely continue to work with her in the future and I couldn’t recommend her highly enough.

Felicity Wood (Yoga Instructor, Bicester)

Jo took my simple brief outline of what I wanted and turned it into everything I wanted and more. Jo was very professional, efficient and she was patient and understanding with the fact that I was not knowledgeable about building websites or what’s involved. By the end of it Jo had given me and my team a training session around how to manage the website. I would highly recommend her!

Sharon Mulholland (Sandcastle Mortgages, Kidlington)

Jo was completely fantastic! I’d been struggling to make a WordPress blog design work and was completely stumped. I made an enquiry to Jo about some help, and she replied within 24 hours. It was easy to agree on a price for the things that needed to be done, and she had fixed everything within 48 hours of the original enquiry. I had thought my problem was too small for someone to help with it, but I was pleasantly surprised that Jo was happy to sort out the small issues with my site for an extremely reasonable fee. Throughout the process, Jo was efficient, effective and stayed in regular communication. She answered all of my questions, even the really idiotic ones, and nothing was too much trouble. The entire experience was great and I would recommend her in a heartbeat to anyone who needs help with a website project – big or small. She is, in short, superb at what she does.

Imogen Goold (Blogger, Oxfordshire)

I wish I had found Jo earlier. We wanted to progress from making simple text edits to getting more out of the CMS. After a very enjoyable training session, we can now design new pages and keep the website organised. Excellent.

Margaret Hildreth (JP Hildreth Ltd, High Wycombe)