image of blog thumbnail

How to Automatically Resize Thumbnails using the Regenerate Thumbnails WordPress Plugin


There’s a lightweight WordPress plugin that can make a big difference to your site’s appearance when you change your theme.

It’s called Regenerate Thumbnails.

What does it do, and why do you need it?

Let’s back up a minute and talk about thumbnails

Thumbnails are the images that ride alongside or above the post snippets on a blog or archive page. WordPress uses the Featured Image to create the thumbnail.

Traditionally, they’ve looked something like this:

image of blog thumbnail images

New themes, though, often want to use bigger thumbnails, like this:

image of blog thumbnail

Let’s say you want to update your theme. How do you resize thumbnails to make them look good without spending a huge amount of time creating new Featured Images for all your posts?

Here’s where the Regenerate Thumbnails plugin enters the picture (pun intended).

What does Regenerate Thumbnails Do?

Here’s what the developer says about Regenerate Thumbnails:

“Regenerate Thumbnails allows you to regenerate the thumbnails for your image attachments. This is very handy if you’ve changed any of your thumbnail dimensions (via Settings -> Media) after previously uploading images or have changed to a theme with different featured post image dimensions.”

In other words, it goes through every featured image in your WordPress site and resizes the thumbnails to the new thumbnail dimensions.

How to Use Regenerate Thumbnails Plugin

#1. Install and activate it the same way you install any other plugin.
#2. Run the Plugin

In your WordPress Dashboard, hover over the Tools menu. You’ll see it listed as Regen. Thumbnails. Click to open it.

image of Regenerate Thumbnails location in WordPress Dashboard

Click the Regenerate All Thumbnails button.

Important: Don’t navigate away from the new page that opens up until the thumbnails have all been regenerated! Depending on your server speed and the number of images on your site, this can take several minutes, so be patient.

As images are processed, you’ll see the status bar move.

image of Regenerate Thumbnails plugin working

When the regeneration is complete, you’ll see a message that looks like this:

image of Regenerate Thumbnails completed

Scroll down to the bottom of the page, It will list all the images that have been processed successfully, and will also show you any errors that may have occurred.

If there were any failures, click the link provided at the top of the page to reprocess those images.

That’s all there is to it!