Regenerate thumbnails in WordPress

Last week I finished a project with thousand images (few hundreds megabytes which is basically unimportant) when I suddenly realized that almost each image file is way larger than it is necessary. For example why I should use a 150×150 image as a 50×50 sideshow thumbnail? Plus there was one more resolution for featured images. So I decided to add those two dimensions to optimize page load speed – this was the easy part. Assuming you’ve already faced with this story you might know that adding  new image resolution will not generate new images automatically.

At first I’ve tried WordPress’s official plugin database but I was not satisfied with the results. I wrote a little plugin on my own for this little task and that plugin is now available for anyone from the WordPress community. You can do selective or total regenerate for your media library. At this time the plugin works well enough for production use but it is not finished yet. I have some ideas to improve its performance. The biggest issue is the limited server-side capabilities (little RAM, insufficient processing power etc) which can be solved with elapsed time and consumed memory.

How to download

You can install ONet Regenerate Thumbnails either via the plugin directory, or by uploading the files to your server. (If you want to contribute the plugin you can find the Git repo at BitBucket).

9 comments - Post a comment

Hello, i like this plugin because it safe a lot of time.
Will be there an update to WordPress 4.4.x?

Best regards,

Well, I’m not quite sure if it will happen and even less sure about when. But I’m glad you like it, I’ll keep it in my mind.

Hi József,

if you need “assistance” to make an update, i could help you. I am coding myself a lot in PHP and so on and have one plugin and other snippets on my website.
You can send me an email if you like.

Best regards,

  • József Koller
  • Like

I’ve wrote you an email, just ping me back 😉

I’ve been following this site for a long time. Very useful articles. I publish my blog articles in your beautiful way. Thank you very much for everything

Thank you for this great plugin. Unfortuneately it is no longer working with WordPress version 4.1. Is there any chance for a update to make it working with WP 4.1 ?

Hi, if I’m using your plugin. There is a collision with NinjaForms ( – The buttons for inserting fields in the email Text are not working if your plugin is activated. Could you fix this? Thanks! BTW: Your plugin is great!

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Cool plugin bro! Thanks a lot.


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