How to change the featured image size of a WordPress theme?

The following are a few featured images related questions asked frequently by our customers.

1. How can I change the featured image sizes shown in the theme?
2. What is the best “featured image size” to upload?
3. Why all of my images are cropped?

Today I am going to answer these questions and provide you a good solution. If you want to skip reading the whole article and need the solution right away please click here to jump into the solution.

What is a Featured Image?

First of all, I will tell you what a featured image is. Featured image is a feature of WordPress that has been provided to be used on themes and plugins. When you write an article you can provide a featured image to give a quick impression of what this article is about.

Theme developers can add any amount of featured image sizes. Themes use these different sized featured images in different locations throughout the theme design. For example on our magazine theme Bam Pro, we use different sized images in the homepage.

What happens when you add a featured image?

When you add a featured image to your post or page, WordPress normally detects it and crops it to the theme defined sizes and plugin defined image sizes. Let’s say your theme has defined 5 featured image sizes and some plugin you have installed has defined another 3 different sizes. Then your server will be filled with 8 images cropped out of the image you provided to be used in different locations. ( Actually 11 images with the WordPress default 3 image sizes ) Oh boy! that’s a huge amount of images on your server right? Let’s talk about it another time. However, please note that any of our themes ( All most all the themes other themes also ) do not delete the original image you upload.

Why you need to change featured image sizes?

Although theme designers use these different sized images to match their theme’s design some users have to change their sizes according to their needs. Some users do not like the theme defined image sizes at all.

Let’s say a user has been using a theme that uses 700px X 400px ( width x height ) sized featured images on the blog archive. And let’s say he has been managing to give the featured images to match that resolution. What happens when he suddenly change the theme that uses different image size for blog archive featured images? All of his old blog archive post images will look dull or meaningless. So in this kind of situation, he may have to use the same old size on the new theme too.

How to change the theme defined featured image sizes? ( Solution )

So how you can display the featured image in the size that you want to display? Actually there are two solutions to this.

Solution 1 : By making a child theme.

The first solution is by making a child theme and changing the image sizes. Since most of our customers do not like coding kind of stuff I am not going to explain that here. I will write another article explaining how to do that.

Solution 2: By using a plugin.

The second and easiest solution is by using the Simple Image Sizes plugin. ( You will see a notification on WordPress saying that the plugin is not tested with the latest version of WordPress. But actually it is working just fine. )

I will guide you to how to use that plugin.

1. First, install and activate the Simple Image Sizes plugin.
2. Then please navigate to Settings > Media on your WordPress dashboard.
3. If you scroll down a little bit on that page you will see image sizes defined by themes and plugins. Normally you can recognize the theme defined image size by the name of the handle. For example, it will display like this > nameofthetheme-image-size-name size. *( For example if the theme is Bam you will see a line called bam-featured size. )

4. Then change the width and height of the image size that you want to change and hit the update button which is relevant to the image size.

5. Final step is to install the Regenerate Thumbnails Plugin and run it once to crop all the images to the new size that is defined by you.

6. That’s it. You have successfully customized your image sizes.

You may wonder how you can know which image use in which place of the theme. Following is the list of default image sizes used in Bam and Bam Pro WordPress themes.

Image Size Name	Image Size	Theme Display Location
bam-large	1400px x 800px	Displays on single post layout, Slider and other Featured Posts Block Widgets
bam-featured	890px X 530px	Displays on blog archives when it has a grid layout and on Posts Block Widgets
bam-list	700px X 465px	Displays on Bam: Posts Block (List Posts) widget
bam-thumb	445px X 265px	Displays on Bam: Posts Block (Style 3) widget, Bam: Posts Block (Style 4) widget and Related posts on single posts.
bam-small	120px X 85px	Displays on Posts Block widgets. ( Small Image )

Following is the list of image sizes of Awaken and Awaken Pro WordPress themes.

Image Size Name	Image Size	Theme Display Location
featured-slider	752px x 440px	Displays on single post layout and on Slider.
featured	388px X 220px	Displays on blog archives and Awaken: Posts Widgets
small-thumb	120px X 85px	Displays on Awaken: Posts widgets as Small Thumbnails and on Related Posts of Single Posts.

I hope this article will help you. Please comment below if you have any questions.