Implementing Custom Image Sizes in WordPress Themes

Posted on 20th June 2023

When it comes to images, WordPress is very flexible. You can easily add custom image sizes to your theme so that users can select the size that they want when they are inserting an image into a post or page. This can be very useful if you have a theme that uses large images or if you want to give users the option to select a smaller image size to save on bandwidth.

In this article, we will show you how to add custom image sizes to your WordPress theme. We will also show you how to crop images to the exact size that you need, how to add custom image sizes to the WordPress media library, and how to use the new image sizes in your theme.

Adding Custom Image Sizes

The first thing that you need to do is add the following code to your theme’s functions.php file. This code will register a new image size with WordPress.

We have added the code for a custom image size that is 400×400 pixels. You can change the dimensions to whatever you want. Just make sure that you change the name of the image size (in our case, it is “custom-size”) to something unique.

You can also crop the image to the exact dimensions that you need by adding an array of cropping positions. For example, if you want to crop the image to the center, you would use the following code:

Now that you have registered your custom image size, you can use it in your theme.

Inserting Images Into Posts and Pages

When you are inserting an image into a post or page, you will see a new “Custom Size” option in the drop-down menu.

Selecting this option will allow you to select the custom image size that you registered earlier.

If you want to use the custom image size in your theme, you can use the WordPress function get_the_post_thumbnail(). This function has two parameters, the first one is the post ID and the second one is the image size.

Here is an example of how you would use this function in your theme:

This code will output the featured image of the post with the ID of “1” in the custom image size that we registered earlier.

Adding Custom Image Sizes to the WordPress Media Library

By default, WordPress will only show you the thumbnail, medium, and large image sizes in the media library. If you want to be able to see all of the custom image sizes that you have added to your theme, you can add the following code to your theme’s functions.php file.

This code will add a new column to the media library that displays all of the registered image sizes.

If you want to add more than one custom image size to the media library, you can use the following code:

In this code, we are adding three custom image sizes to the media library.

Using the New Image Sizes in Your Theme

If you want to use the new image sizes in your theme, you can use the WordPress function wp_get_attachment_image_src(). This function will return an array with the image URL, the width, and the height of the image.

Here is an example of how you would use this function:

This code will output the URL of the image, the width, and the height.

You can also use the WordPress function wp_get_attachment_image() to directly output the image tag. This function has three parameters, the first one is the post ID, the second one is the image size, and the third one is an array of attributes.

Here is an example of how you would use this function:

This code will output the image tag with the post ID of “1” and the custom image size that we registered earlier.

Conclusion

In this article, we showed you how to add custom image sizes to your WordPress theme. We also showed you how to crop images to the exact size that you need, how to add custom image sizes to the WordPress media library, and how to use the new image sizes in your theme.

If you’re looking to add custom image sizes to your WordPress theme, you’ll first need to add some code to your functions.php file. Here’s the code you’ll need to add:

Replace ‘custom-size’ with the name you want to use for your custom image size, and change the width and height values to the dimensions you need. The ‘true’ value for the last parameter tells WordPress to crop the image to the exact dimensions you’ve specified. If you leave this out, WordPress will resize your image to fit within the specified dimensions, but it won’t crop it.

Once you’ve added this code, you can use the new image size in your theme by using the following code in your template files:

Replace ‘custom-size’ with the name you used in the functions.php file.

You can also use the new image size when inserting images into posts and pages using the WordPress editor. When you click on the ‘Insert Media’ button, you’ll see a list of image sizes to choose from in the ‘Attachment Display Settings’ section.

If you want to add more than one custom image size, you can just add more lines of code to your functions.php file. For example, if you wanted to add a second image size called ‘medium’, you would add the following code:

You can then use either of these image sizes in your theme templates or when inserting images into posts and pages.

When adding the code to your theme, you need to make sure that you include the images/sizes folder and register the size using the add_image_size() function. You can add the code to your theme’s functions.php file or create a new plugin.

Once you have registered the custom image size, you can use it in your theme. You can use the WordPress core functions to get the image URL or use a plugin like Advanced Custom Fields to get the image field and return the image URL.

You can also use the_post_thumbnail() function to output the image tag with the custom size. You just need to pass the custom size name to the function.

You can use the wp_get_attachment_image_src() function to get the image URL and pass it to the img src attribute.

You can use the_post_thumbnail() function to output the image tag with the custom size. You just need to pass the custom size name to the function.

Here’s an example of how to use the_post_thumbnail() function:

And here’s an example of how to use the wp_get_attachment_image_src() function:

ID ), ‘custom-size’ );

echo ‘‘;

?>