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Regenerate Thumbnails
Regenerate the thumbnails for one or more of your image uploads. Useful when changing their sizes or your theme.
The facts
- Rating
- 4.6★ from 395
- Active installs
- 1M+
- Price
- Free
- Last updated
- 20 Aug 2025
- Added
- Aug 2008
- Requires WP
- 4.7
- Tested up to
- WP 6.8.8
- Requires PHP
- 5.2.4
- Downloads
- 22,815,259
Our analysis
AI-assistedRegenerate Thumbnails is a WordPress plugin that allows you to regenerate thumbnail sizes for images in your Media Library. You can use it when new thumbnail sizes are added, existing sizes are changed, or when switching to a new theme that requires different featured image dimensions.
Additionally, the plugin can delete old, unused thumbnails to help free up server space. It is suitable for users who need to manage image sizes effectively within their WordPress sites.
Best for: This plugin is best for WordPress users needing to manage image thumbnails after changes to themes or settings.
What it does well
- ✓Regenerates thumbnail sizes for existing images
- ✓Deletes old, unused thumbnails to save space
- ✓Free to use via the WordPress.org directory
- ✓Active installation count over 1,000,000
- ✓Maintained by Automattic and the WordPress community
Where it falls short
- •No additional features or options mentioned
- •Limited to thumbnail management without advanced functionality
Verdict
Regenerate Thumbnails is a straightforward tool for managing image sizes, particularly useful for those who frequently update their media settings or themes.
From the developer
Alex Mills's own description of Regenerate Thumbnails, lightly tidied.
Regenerate Thumbnails allows you to regenerate all thumbnail sizes for one or more images that have been uploaded to your Media Library.
This is useful for situations such as:
- A new thumbnail size has been added and you want past uploads to have a thumbnail in that size.
- You’ve changed the dimensions of an existing thumbnail size, for example via Settings â Media.
- You’ve switched to a new WordPress theme that uses featured images of a different size.
It also offers the ability to delete old, unused thumbnails in order to free up server space.
In Memory of Alex Mills
In February 2019 Alex Mills, the author of this plugin, passed away. He leaves behind a number of plugins which will be maintained by Automattic and members of the WordPress community. If this plugin is useful to you please consider donating to the Oregon Health and Science University. You can find more information here.
Alternatives
WP-CLI
If you have command line access to your server, I highly recommend using WP-CLI instead of this plugin as it’s faster (no HTTP requests overhead) and can be run inside of a screen for those with many thumbnails. For details, see the documentation of its media regenerate command.
Jetpack’s Photon Module
Jetpack is a plugin by Automattic, makers of WordPress.com. It gives your self-hosted WordPress site some of the functionality that is available to WordPress.com-hosted sites.
The Photon module makes the images on your site be served from WordPress.com’s global content delivery network (CDN) which should speed up the loading of images. Importantly though it can create thumbnails on the fly which means you’ll never need to use this plugin.
I personally use Photon on my own website.
Disclaimer: I work for Automattic but I would recommend Photon even if I didn’t.
Need Help? Found A Bug? Want To Contribute Code?
Support for this plugin is provided via the WordPress.org forums.
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