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How to Regenerate Thumbnails for WordPress Image Attachments

updated on May 16, 2017
How to Regenerate Thumbnails for WordPress Image Attachments By default, WordPress automatically creates copies of different sizes for your image attachments so that an optimized version of images will be applied for your website. However, there are some instances when you have a strong desire to regenerate thumbnails for WordPress image attachments. For example, your old uploads cannot well display if you have made some changes to your themes.

What you primarily have in mind is to set new image sizes via Settings > Media. But it does not make a difference to your previously uploaded files. Instead, to complete the adjustment of all your image attachments, you need to take different measures for your new images and uploaded files. Therefore, this article will not only guide you on how to resize images for new images via Settings > Media but also recommend a plugin to help you adjust thumbnails for the images which have been uploaded to your blog.

Regenerate Thumbnails for New Images

Firstly, we turn our eyes towards the future media files to ease your burden. With a click on Settings > Media, you can directly go to the media settings page where you have the freedom to determine the dimensions for the new images in pixels.

When you add an image to your Media Library, three copies will be made in thumbnail size, medium size, and large size. On this page, you are free to alter the default sizes accordingly. And there is a checkbox available to crop thumbnail to exact dimensions. By pressing the Save Changes button, your new images will be showcased according to your settings.

New Images

Regenerate Thumbnails for Old Images

When it comes to your old images, there is an exclusive plugin – Regenerate Thumbnails – which enables you to regenerate all thumbnails or some of them after changing the thumbnail sizes. After our test, we deeply understand why this plugin has served more than 1 million users and achieved more than 4.5 out of 5 stars.

The first step is to search for "Regenerate Thumbnails" on the result screen of Plugins > Add New. After a click on "Install Now" and "Activate", this plugin is ready for you to use. You can get more detailed steps on how to install the plugin.

Regenerate Thumbnails

On the Tools > Regen. Thumbnails page, you are able to regenerate thumbnails for all images which you have uploaded to your WordPress site. To start with, you need to press the Regenerate All Thumbnails button.

Tools Menu

At this moment, you will be brought into a window where you need to be patient with the regeneration of all your images. It will take a while especially when there are too many uploads in your Media Library. The below processing bar will show you how far you are now in. If you are not satisfied with the results, you can restore your thumbnail dimensions by clicking "Regenerate All Thumbnails" again on the former page.

Old Image

In addition, it is possible for you to resize specific images if you are using WordPress 3.1. On your Media Library page, you need to choose "Regenerate Thumbnails" from the dropdown next to the Apply button. Having selected the images, you can regenerate thumbnails for them after a click on "Apply".

Specific Image

Note: Though you have regenerated thumbnails for your image attachments, you can never worry about affecting the original uploads because more copies of different sizes are created.