Regenerate Thumbnails

What is Regenerate Thumbnails?

Regenerate Thumbnails is a focused utility plugin that rebuilds all image sizes for media uploads. It solves a specific problem: when you change your theme or update your media settings, existing images lack the new dimensions. This plugin fills that gap by regenerating every thumbnail size for selected images in your Media Library. It also cleans up old, unused thumbnails to save server space.

The plugin was created by Alex Mills, a developer who passed away in February 2019. Since then, Automattic and community members have maintained it. It has been active for 18 years, making it one of the oldest plugins in the repository. With over 1.0 million active installs and a 4.6 out of 5 rating from 395 reviews, it remains a trusted tool. Notably, 86% of those ratings are 6% are one-star.

Key Features of Regenerate Thumbnails

• Bulk Regeneration: Rebuild all thumbnail sizes for one or multiple images at once.
• New Size Support: Create thumbnails for past uploads after adding a new image size.
• Dimension Updates: Apply changed width or height values from Settings → Media to existing images.
• Theme Switch Handling: Regenerate featured images to match a new theme’s required dimensions.
• Unused Thumbnail Deletion: Remove leftover image files that no longer correspond to any registered size.
• Admin-Only Operation: Runs entirely in the WordPress admin area without affecting frontend visitors.
• GDPR Compliant Design: Does not log or transmit any user data according to the plugin author.

Who Should Use Regenerate Thumbnails?

This plugin is ideal for site owners who change themes or media settings regularly. It suits beginners because it requires no coding knowledge. You simply navigate to Tools → Regenerate Thumbnails and select images. It also helps developers who maintain multiple sites and need to apply new thumbnail sizes after updates. The 1.0 million active installs show it is a go-to solution for this narrow but essential task.

It is less useful for sites using Jetpack’s Photon module, which creates thumbnails on the fly from a CDN. The plugin author recommends WP-CLI for command-line users, as it avoids HTTP overhead. However, for most WordPress administrators without server access, Regenerate Thumbnails remains the simplest option. The 4.6 rating reflects its reliability for this specific workflow.

Installation & Setup

Installation takes under a minute. Go to Plugins → Add New in your admin area, search for “Regenerate Thumbnails,” click install, then activate. After activation, you find it under Tools → Regenerate Thumbnails. The plugin requires WordPress 4.7 or higher and PHP 5.2.4 or later, making it compatible with almost any modern site.

Support & Community

Support is provided through the WordPress.org forums. In the last two months, there were 0 open threads and 0 resolved threads, resulting in a 0% resolution rate. This likely indicates the plugin is stable rather than neglected. The 7% one-star ratings often stem from conflicts with aggressive caching or server timeouts during large regeneration jobs. The source code is available on GitHub for those who want to contribute or report bugs. Despite the author’s passing, Automattic’s maintenance ensures continued compatibility with WordPress 6.8.5.