How to regenerate thumbnail images in WordPress

Have you ever changed WordPress themes just to find that your thumbnails are now distorted?

If you have, don’t worry. This is not uncommon, however frustrating.

If you frequently change the WordPress theme, the thumbnails that appear next to your blog post will be loaded in the wrong dimensions. This is because themes that have different aspect ratios and dimensions for your thumbnails than the previous theme will be loaded incorrectly. The end result – thumbnails of images that are inaccurately displayed to visitors to your site.

Rather sometimes when you go to Settings > Average to solve the problem by changing the existing dimensions, the problem is not solved.

So what do you do?

Well, I have a solution for you. Today, we’ll look at how you can regenerate thumbnail sizes on your WordPress site so that your site’s images no longer appear distorted.

Overview of WordPress thumbnail images

By default, when you upload an image to your site, WordPress automatically creates images of different sizes and saves them for later use. In fact, the default setting for WordPress thumbnails is 150px to 150px, which is square. So you can choose from a medium default size of 600 x 600 pixels and a large one of 1024 x 1024 pixels. Both dimensions of the image are again square.

These image dimensions are required to properly display images on your site, regardless of their actual size. These sizes can be easily changed by going to Settings > Average.

regenerate-thumbnail-media settings

The problem is that adjusting your media settings may not always work to properly display images on your site. Additionally, when you change themes, your images are saved many times in newly defined dimensions and sizes that are significantly different from the sizes of the original theme to make them look convenient for viewers.

Unfortunately, these new image sizes only apply to uploaded images after activating a new topic. This means that any old images you have stored in your WordPress database will remain incorrectly sized and will appear distorted on the front-end of your site.

To resolve the problem with distorted thumbnails, you must recreate new sizes for all previously uploaded images.

Fortunately, this is an easy fix using the free one Regenerate thumbnails plugin found in WordPress repository. The great thing about this plugin is that you can regenerate thumbnails for all image uploads, single image uploads or specific bulk image uploads.

How to regenerate thumbnail images in WordPress

Let’s take a look at the required steps to regenerate new image thumbnail sizes on your WordPress site using Regenerate Thumbnails.


Step 1: Installation and activation

Go to first Plugins > Add a new one on the WordPress taskbar.


Find Regenerate Thumbnails and click Install now and activate to make this plugin work on your site.

Step 2: Restore your thumbnails

Then go to Tools > Rain. Thumbnails start the regeneration process on the WordPress taskbar.

regenerate-thumbnails-we start

After clicking on Rain. Thumbnails menu item, you will see a screen explaining the purpose of this plugin. In addition, you will see Regenerate all thumbnails button so you can resize all your old image sizes to fit the dimensions of your new theme.


Just click on Regenerate all thumbnails button and all your images are regenerated and displayed correctly on the front-end of your site.

regenerate-thumbnails-regenerate-all-thumbnails in the process

As your images regenerate, you will notice a progress bar, a button to abort the regeneration process, and debugging information such as overall images, image size, and size failure. This may take a while to complete, especially if you have a lot of old images to regenerate. They recommend that you stay patient and let the plugin work on your spell.

When done, a completion notification will be displayed informing you of the number of images that have been successfully regenerated, as well as the number of failures. In addition, you will be able to try the process of recovering failed images. All you have to do is click on the available link.


Note that thumbnail regeneration is not reversible with this plugin. Once all the dimensions of your image have been changed, it will not be possible to go back. However, the plugin developer is proposing a solution.

If you decide you don’t want your images to regenerate, simply resize the thumbnails back to their old values ​​and click Regenerate all thumbnails button again.

Step 3: Regenerate specific images

If you prefer to regenerate specific images, not all, Regenerate Thumbnails has a solution for you.

To do this, go to Average > Library and make sure you are in the list view. Then place the cursor on the image you want to regenerate and click on it Regenerate thumbnails.


Then you will see the same screen that is generated when you change all your images at once.


Remember that regenerating the image sizes on your site to match the requirements of your new theme will not affect the upload of the original image. In fact, it only creates additional copies of images in newly defined image sizes for proper display on the front-end of your site.

In addition, it does not delete previously created image sizes. However, if you feel that these image sizes are not available on your site, you can delete them from your media library to save on server resources.

Final thoughts

Finally, inconsistent or downright distorted images displayed on your WordPress site will not only make site visitors look unprofessional, but may result in certain technical glitches that may adversely affect the user experience of site visitors. It is very important to maintain consistency when it comes to thumbnails of your website. The only solution is often to regenerate them all to look the same.

If you found this article, read our article on choosing a WordPress theme (the ultimate guide).

Have you ever encountered problems with incorrect display of thumbnails of your WordPress site? If you have any questions or feedback, please let us know in the comments below!

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