AJAX Thumbnail Rebuild allows you to rebuild all thumbnails on your site. There are already some plugins available for this, but they have one thing in common: All thumbnails are rebuilt in a single step. This works fine when you don’t have that many photos on your site. When you have a lot of full-size photos, the script on the server side takes a long time to run. Unfortunately the time a script is allowed to run is limited, which sets an upper limit to the number of thumbnails you can regenerate. This number depends on the server configuration and the computing power your server has available. When you get over this limit, you won’t be able to rebuild your thumbnails.
Why would you want to rebuild your thumbnails? WordPress allows you to change the size of thumbnails. This way, you can make the size of thumbnails fit the design of your website. When you change the size to fit for a new theme, all future photos you are going to upload will have this new size. Your old thumbnails won’t be resized. That’s where this plugin comes into action. After changing the image sizes, you can rebuild all thumbnails. But instead of telling the server to recreate all thumbnails at once, they are rebuilt one after another. Rebuilding thumbnails for one photo won’t take all too long, so you won’t run into any script timeouts. Note that you still have to wait until all thumbnails have been rebuilt. If you close the page before the task is completed, you have to start all over again.
You can also select the thumbnail sizes you want to rebuild, so that you don’t need to recreate all images if you’ve just changed one thumbnail-size. You can also choose to only rebuild post thumbnails (featured images).
Upload the plugin to your blog, activate it, done. You can then rebuild all thumbnails in the tools section (Tools -> Rebuild Thumbnails).
We’ve been using this plugin for years at our site. However, I noted in January 2017 that a little warning pops up saying that this plugin hasn’t been updated in a while, and it cautions the reader that the plugin may not work. Well I just want you to know that it continues to function beautifully on the latest WordPress core (4.7.1 as I’m writing this).
Besides our production site, we have created various other versions of our site on virtual machines where we do our development work. Since our site has a huge number of images, we just do an SQL query to get a list of the original uploads, and then we only have to move these original photos onto the development versions of our site. After the originals are in place, we use AJAX Thumbnail Rebuild to just make the thumbnail sizes that we actually use. Besides freeing up time and bandwidth by only copying a fraction of the images at our production site, it also keeps our uploads directories from getting filled up with image sizes that various themes have created in the past which we aren’t currently using.
In addition if there are image sizes that you only use when displaying featured images, you can constrain AJAX Thumbnail Rebuild to only make those sizes for your featured images. For instance, at our site we only use the smallest thumbnail size to show related posts, and this only makes use of the featured images for the related posts. So we can skip making the smallest thumbnails for the vast majority of our photos.
It started and got stuck after a few images.
Saves tons of effort when one wants to simply rebuild all their thumbnails at one go without their wp-admin timing out.
I CAN NOT believe this plugin still works in 2016 !!!
This plugin has magic, so fast & light-weight.
I’ve changed the different image size quite a few time on my theme, so that proved very usefull and does the job perfectly.
Contributors & Developers
“AJAX Thumbnail Rebuild” is open source software. The following people have contributed to this plugin.Contributors
Interested in development?
- FIX: An issue where rebuilding thumbnails in the media gallery
would not work
- FIX: An issue where the plugin would sometimes break the media gallery.
- NEW: Rebuild thumbnails of single images on the media attachment page.
- NEW: Checkboxes can be activated by clicking on text.
- NEW: Slovak translation, provided by Branco Radenovich.
- FIX: Don’t create metadata with empty size when original image is smaller
than the target size.
- FIX: Don’t forget metadata for sizes that aren’t rebuilt.
- FIX: Option to only rebuild featured images should now work correctly.
- FIX: Don’t fail if there are no attachments.
- NEW: It’s now possible to toggle all selected sizes.
- NEW: Added translation: German.
- Add option to only rebuild post thumbnails (featured images)
- Tested with WordPress 3.2
- Fixed: Show correct height value for thumbnails.
- You can now select which thumbnail sizes you want to rebuild. Thanks to Nicolas Juen!
- Tested with WordPress 3.0
- Initial release