How to Regenerate Thumbnails in WordPress

Last Updated on May 28, 2026

Images are an important part of every WordPress website. They improve user experience, make blog posts attractive, and help with SEO. However, sometimes image thumbnails in WordPress may appear broken, blurry, stretched, or missing after changing themes or image settings. This is where regenerating thumbnails becomes necessary.

In this guide, you will learn how to regenerate thumbnails in WordPress step by step. We will also explain why thumbnail regeneration is important and how you can do it safely without affecting your website.

You may also want to learn how to optimize images in WordPress to improve website speed and SEO performance.

What Does Regenerate Thumbnails Mean in WordPress?

Whenever you upload an image to WordPress, the system automatically creates multiple image sizes, such as thumbnail, medium, large, and custom sizes required by your theme or plugins.

If you change your WordPress theme or modify image dimensions in the settings, the old images do not automatically update. As a result, your website may show incorrectly sized images.

Regenerating thumbnails means creating new image sizes for previously uploaded images according to your current WordPress settings.

Why You May Need to Regenerate Thumbnails

There are several reasons why website owners regenerate thumbnails in WordPress:

• You changed your WordPress theme
• You updated the image size settings
• Your thumbnails appear blurry or stretched
• You installed a new plugin requiring custom image sizes
• Your featured images are not displaying correctly
• You want to remove unused image sizes

Regenerating thumbnails helps your website display properly optimized images across all pages.

If your website feels slow after uploading media files, check our guide on the best WordPress image optimization plugins.

How to Regenerate Thumbnails in WordPress

There are different ways to regenerate thumbnails in WordPress. The easiest method is using a plugin.

Method 1: Using the Regenerate Thumbnails Plugin

The simplest and most beginner-friendly method is using the popular Regenerate Thumbnails plugin.

Follow these steps:

1. Login to your WordPress dashboard
2. Go to Plugins → Add New
3. Search for Regenerate Thumbnails
4. Install and activate the plugin
5. Go to Tools → Regenerate Thumbnails
6. Click the Regenerate Thumbnails for All Attachments button

The plugin will now recreate all image thumbnails based on your current settings.

Depending on the number of images on your website, the process may take several minutes.

To improve image performance further, you can learn more about modern image formats like WebP from Google Developers WebP Guide.

Method 2: Regenerate Thumbnails for Specific Images

If you only want to regenerate thumbnails for selected images, WordPress plugins also allow that.

Here is how:

1. Go to Media → Library
2. Switch to list view
3. Hover over the image you want to fix
4. Click Regenerate Thumbnails

This method is useful when only a few images have display issues.

Method 3: Using WP-CLI

Advanced users can regenerate thumbnails using WP-CLI.

Use the following command:

wp media regenerate

If you want to skip existing thumbnails and regenerate only missing ones, use:

wp media regenerate --skip-delete

This method is faster for large WordPress websites.

You can download the popular Regenerate Thumbnails plugin directly from the official WordPress plugin repository: Regenerate Thumbnails Plugin.

Things to Do Before Regenerating Thumbnails

Before starting the process, it is always a good idea to follow some safety steps.

Create a Website Backup

Although thumbnail regeneration is generally safe, you should always create a complete website backup before making changes.

A backup protects your files and database if something unexpected happens.

Check Server Resources

Regenerating thousands of images can consume server memory and CPU resources.

If you have a large media library, perform the process during low-traffic hours.

Remove Unused Image Sizes

Some WordPress themes and plugins create unnecessary image sizes.

Removing unused sizes can save disk space and improve performance.

Benefits of Regenerating Thumbnails in WordPress

Regenerating thumbnails provides several advantages:

• Improves image quality
• Fixes broken thumbnails
• Enhances website appearance
• Ensures theme compatibility
• Improves page loading speed
• Helps maintain SEO optimization

Properly optimized images can also improve user experience and reduce bounce rates.

For beginners, our tutorial on how to change a WordPress theme safely can help avoid thumbnail and layout issues.

Common Problems While Regenerating Thumbnails

Timeout Errors

If your hosting server has low resources, the process may stop before completion.

In such cases, regenerate thumbnails in smaller batches or contact your hosting provider.

Missing Images

If original image files are deleted from the server, WordPress cannot recreate thumbnails.

Always ensure original images exist in the uploads folder.

Slow Website Performance

Large image processing can temporarily slow down your website.

This is normal, and performance should return to normal once the process finishes.

For website performance recommendations, refer to Google PageSpeed Insights.

Best Practices for WordPress Images

To avoid thumbnail problems in the future, follow these best practices:

• Upload optimized images
• Use modern image formats like WebP
• Compress images before uploading
• Keep image dimensions consistent
• Use reliable WordPress themes and plugins
• Regularly clean unused media files

Good image management improves both SEO and website speed.

You can also read our article about fixing broken images in WordPress.

Conclusion

Now you know how to regenerate thumbnails in WordPress using different methods. Whether you use a plugin, WP-CLI, or regenerate specific images, the process helps fix image display problems and improves your website’s appearance.

If you recently changed your WordPress theme or image settings, regenerating thumbnails is one of the most important maintenance tasks you should perform.

Always remember to create a backup before making major changes to your website.

WordPress officially explains image handling and media settings in its documentation on WordPress Documentation.