How to create custom image sizes in WordPress, as a beginner?

Here is a quick and easy beginner guide on how to create custom image sizes in WordPress. Instead of writing a long introduction that no one really wants to read let’s get right to the different possible solutions and talk about why it’s so important to be able to do this and what the differences are between the possible methods after. So here it is: the easiest and fastest tutorial on how to create custom image sizes in WordPress. Scroll down below to find the tutorial!

Why is it so important to be able to do this?

Firstly, let’s quickly go over why it is so important to be able to do this. Normally, WordPress has its own limited default image sizes. Therefore when you upload an image, you create an extra file in this odd size. When you create your own custom image sizes you can save hours of time editing your images within WordPress, and just automatically generate them. Using precisely sized images will improve load times and with that your SEO ranking.

So how do you create custom image sizes in WordPress?

There are a couple of ways to create custom image sizes in WordPress. 

  1. Number one, and this is the one we absolutely recommend to beginners and anyone who wants to save a lot of time and effort: Download the Jixxio Media Management plugin. This plugin has everything you will ever need for media. It not only allows you to create custom image sizes with a single click and also offers tons of other features: regenerating thumbnails, adding custom media categories and media fields, optimizing images on upload and one-click image replacement. (Jixxio got first place in our Top 5 Best WordPress Plugins for Image Management 2019) It requires a small investment of just $20 but you get at least three times your money is worth. This plugin will save you so much time and effort. Once you get the plugin all you have to do is simply fill in your desired image size, say if you want to crop the image yes or no, give it an obvious name and click save. That’s it!  You can get it now by clicking on the image below!
Use Jixxio to create custom image sizes in WordPress
  1. The second way is a lot more difficult, especially for anyone who has not been coding for many years already, and it’s also very time consuming, however it is possible. It requires you to do complicated editing in your theme’s function.php file and hard-code image sizes there. After that there is no way to change them except editing the functions.php file again. This will also only affect new images you upload to your WordPress Media. To create different image sizes with the images already uploaded, you need to regenerate your thumbnail, and there is no good or easy way to do this without the help of a plugin. Lastly you need to integrate your custom images in WordPress and this also requires additional coding or another separate plugin. If you don’t integrate your image sizes, they will e.g. not show up in Gutenberg. If you don’t want to mess with all this, use a plugin like Jixxio.

In short: How to create custom image sizes in WordPress?

We highly recommend you get the Jixxio Media Manager plugin to help you out with this and any other future media related topics. It is quick and easy to use and allows you to create custom image sizes in the most efficient way. If you do not have $20 dollars to spend you can go through the process of coding as described in step two. If you did decide to grab the Jixxio plugin they have a great FAQ where they explain very clearly step by step how to do everything their plugin provides. Here is their explanation for How to create custom image sizes in WordPress:


Step 1. Go to Register Image Sizes. You will see an overview of the registered image sizes and you can also create your own custom image sizes here.

Image Size Name: Enter a unique name*

Width and Height: Resizes the image file to your desired pixel format, without stretching or leaving a blank space.

Crop: Selecting the crop option will cut out an area of your image, from the middle, to the size of your selected width and height.

Step 2: Click Save Changes to register the image size.

Step 3: IMPORTANT: After creating an image size, you MUST run Regenerate Thumbnails.

*NOTE: No spaces or special characters allowed. Only letters, numbers, minus signs and underscores. Always check the name in the table before using it to avoid confusions.