AJAX Thumbnail Rebuild – Plugin Spotlight

I have a handful of plugins I use on my sites, and I’d like to talk about one in particular I use very often, specially when I am working with or editing a new theme. AJAX Thumbnail Rebuild

Whenever you switch themes, or create your own theme and add or change the size of the post thumbnails (or any other image) it might not display as it should. This is because WordPress didn’t know about your new thumbnail size when it created the thumbnails for your previous posts.

What this plugin does is, it creates your new image sizes for all the images on your site. For example, on my own site, my post thumbnails are 140×140. If I were to use another theme such as Blue Splatter which uses a 645×175 post thumbnail, I wouldn’t have that size image within my media. This plugin would create the 645×175 size so all of my old posts would display the thumbnail properly.


It’s very easy to use, just goto the plugin page in your admin section and run it, once it’s done (takes about 3 minutes for my site) you’ll have your new thumbnail size for each image.

12 thoughts on “AJAX Thumbnail Rebuild – Plugin Spotlight

    1. Zeaks

      This is true, but you can go and remove the un-used image sizes manually from media, this would really only be an issue if disk space was limited. I would rather have extra images than images in posts that were the wrong size 😛

    1. Zeaks

      No idea sorry, I see you’ve already asked on the wordpress.org forums as well. Have you tried using an earlier version? You said you’ve used it before so maybe it’s a version specific issue with your site.

    2. Chris

      It’s possible that the process has reached the PHP memory limit – either because not enough is allocated for use, or you have a lot of images to process and it’s timing out. I have run into situations in the past where WordPress process will fail with a 500 error on admin-ajax.php. In your particular situation, you can try one or both of the following:

      1. If you have access to your server’s .htaccess file, try bumping up the PHP memory allocation by adding this to the top of the file (you could accomplish a similar configuration via httpd.conf if you have access to it and are familiar with changing its parameters):

      #PHP max upload values
      php_value memory_limit 128M

      2. If you don’t have access to .htaccess or the above did not work, you might try editing the plugin so that you can process your thumbnail in batches. On lines 179 and 189 of the ajax-thumbnail-rebuild.php file, you can set the ‘numberposts’ value to something other than -1, say 1000. You can then define an offset paramater with ‘offset’ => ‘1001’ after processing your first batch. Add this paramater to both sections starting at 177 and 187, respectively.

      I had run into the same 500 error and got around it by using these steps. Your results may vary, of course. Remember: be sure to back up your database and whatever other files you happen to work on before proceeding with something like this.

      Best of luck.

      1. ddeconin

        Unfortunately I cannot set the memory limit to 128 since Im on a shared host and the provider does not allow it.
        I tried the numberposts to 1 , but still I get the error 500 :-(
        Thx for trying trying to help out !

  1. samundri357

    Hello I delete ajax-thumbnail-rebuild plugin from my website but there is still working on my website can you tell please which file i remove or some code to remove.Please help me because i dont want to use more this plugin more on my that site Thanks
    Waiting for soon reply.

  2. jisela cordoba

    hl hoy les cotare que me paso en la escuela
    me mandaron a que le dijiera a mis padres
    como fue la historia de mi nombre y como
    me pondrian entonces mis padres dijieron ha usted le ibamos a poner chipichipa
    y me pusieron fue jisela y el lunes pasado me pregunta la maestra como le iba ha poner ha usted jisela y yo le dije maestra ami me iban ha poner chipichipi y dijo la maestras pero que nombre tan asqueroso y yo le dije es que el suyo es muy lindo y ella dijo si y le dije repitamelo otra vesz y me lo dijo y se llamaba senaida y yo dije mejor es el mio

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