Regenerate Thumbnails

Plugin Description:

Regenerate Thumbnails allows you to regenerate all thumbnail sizes for one or more images that have been uploaded to your Media Library.

This is useful for situations such as:

  • A new thumbnail size has been added and you want past uploads to have a thumbnail in that size.
  • You’ve changed the dimensions of an existing thumbnail size, for example via Settings ? Media.
  • You’ve switched to a new WordPress theme that uses featured images of a different size.



823 thoughts on “Regenerate Thumbnails

  1. This plugin not work in my site, i’m using wordpress version 3.9. If i using this plugin always show:

    function (){if(h){var d=h.length;!function f(b){n.each(b,function(b,c){var d=n.type(c);”function”===d?a.unique&&k.has(c)||h.push(c):c&&c.length&&”string”!==d&&f(c)})}(arguments),b?e=h.length:c&&(g=d,j(c))}return this}

    And i already contact suport hosting, but he says:

    When you stated your site was down, you did not state the error or show an error was happening in the backend. Could you please contact the maker of the plugin and make sure it works with your version of WordPress whether 3.9 or 3.8.1 depending on what you are running. Also please ask him/her what necessary PHP extensions are needed to run their plugin. Is it GD Or Imagick in php? Please advise and get back to me with this info.

  2. Hi Alex,

    Got me an interesting problem here and I’d appreciate your input. No doubt the resolution is simple, but I’ve yet to find it!

    The story is as follows:

    1: Regenerate Thumbnails plugin worked fine with WP3.8.3, it found all pics uploaded via Media > Add New regardless of where I moved
    them to afterwards.

    2. Upgraded WP from 3.8.3 to 3.9

    3. WP3.9 didn’t work for me, after discussions with WP and with host the consensus was to roll back to WP3.8.3 by having host do a restore using data from their monthly backup.

    4. Before they did the restore they made a “safety copy” of my uploads folder.

    5. They did the restore. I was back on WP3.8.3 and all was well.

    6. They copied back my uploads folder. The pics are back

    7. Now, when I run Regenerate Thumbnails I get many errors (1006 files of which 293 fail to resize), a typical error-message is: “wildsat014-1531246085-O” (ID 11177) failed to resize. The error message was: The originally uploaded image file cannot be found at /home1/beardedg/public_html/wp-content/uploads/2014/04/wildsat014-1531246085-O.jpg
    The copy-back of my uploads folder placed that file at

    Site is

    I’d appreciate your thoughts as to what’s gone wrong and how to fix it?

  3. Update.

    I’m making some progress here…

    If, using cpanel, I move the misplaced files back to where Regenerate Thumbnails expected to find them, and then move them (using Media File Manager) back to where I want them, they will regenerate.

    However, there are a few files that I just don’t have anywhere in my uploads, so I can’t do the “move-then-move back” dodge. Regenerate Thumbnails still reports “cannot be found” errors when it tries to process them. Is there a way to stop that happening?

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  8. Hi there!

    I’ve used your wonderful plugin when I changed to a custom theme. But if I upload new pictures that I use for thumbnails, do I have to regenerate again? Or is it only for old pictures? I’ve deactivated the plugin after I installed the new plugin and didn’t regenerate after that. So I was wondering if that is necessary 🙂

    Thanks in advance!

    The Netherlands

  9. hi i’m currently having an issue with regenerating thumbnail plugin. i reinstalled it and it still gives me the same error. i’m not sure what is wrong with it

    Error Message:
    function (){if(h){var d=h.length;!function f(b){n.each(b,function(b,c){var d=n.type(c);”function”===d?a.unique&&k.has(c)||h.push(c):c&&c.length&&”string”!==d&&f(c)})}(arguments),b?e=h.length:c&&(g=d,j(c))}return this}

  10. Hi there,
    I’ve ran the plugin and the thumbnails are showing up, but none of my images in posts are showing up, just the image title, my whole blog is pretty much ruined unless I reupload all the photos. I was wondering if there was an easier way around this. Thanks!

  11. Yep, me as well: function (){if(h){var d=h.length;!function f(b){n.each(b,function(b,c){var d=n.type(c);”function”===d?a.unique&&k.has(c)||h.push(c):c&&c.length&&”string”!==d&&f(c)})}(arguments),b?e=h.length:c&&(g=d,j(c))}return this}

    Seems maybe an incompatibility with the WP 3.9.1 jquery or jquery ui version?

    • Scratch that. It’s actually a permission issue. I can see the response in console from admin-ajax. Warning: imagejpeg(): Unable to open ‘wp-content/uploads/2014/6/example-image.jpg’ for writing: Permission denied in wp-includes/class-wp-image-editor.php on line 391.

      • Thanks Wilson. Was having the same issue which was resolved once I’d changed permissions.

    • For a reason I have still yet to figure out, jQuery freaks out and outputs this source code if the AJAX response is not valid JSON. This usually happens when a PHP error occurs, despite my attempts to silence them.

      • Any progress on this? I just got the same thing today when trying to regenerate and hardly any of my photos were resized. Just that same function message displayed for each one. I changed permissions as was written in one thread I found, but all the photos disappeared.
        This is the message for almost all photos:
        function (){if(h){var d=h.length;!function f(b){m.each(b,function(b,c){var d=m.type(c);”function”===d?a.unique&&k.has(c)||h.push(c):c&&c.length&&”string”!==d&&f(c)})}(arguments),b?e=h.length:c&&(g=d,j(c))}return this}

        The photos are showing at different sizes currently in the shop page. A bit embarrassing…

        Thanks in advance for your help.

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  16. If you have the “blurry” images problem when you go back to another theme, you can fix it by regenerating thumbnails to that specific theme (run the regen again on that theme), that fixed it for me.

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  19. Your plugin is awesome! A client asked me to resize the thumbnails in their e-commerce site and there are hundreds of images. Your plugin regenerated all of these in just a few minutes and even went back to retry the failed ones!

    There needs to be more robust and straight to the point plugins like yours. Thank you! You’re awesome!

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  22. Great plugin, saved me a heck load of time with my thumbnails.

    Searched the forum on how to resume thumbnail regeneration for whatever reason (server timeout, connection stuffed up etc) but found nothing that involves minimal coding.

    So here’s an easy fix – but you have only one shot. The plugin is designed to regenerate thumbnails following product ID in descending order. Meaning that if you have 10000 products, the plugin starts at product #10000, then #9999, #9998 and so on.

    If it cuts off at #5000 and you just want to regen thumbnails for #4999 to #1, edit the regenerate-thumbnails.php file at line #167:

    (As usual, backup the original file first before making this edit.)

    if ( ! $images = $wpdb->get_results( “SELECT ID FROM $wpdb->posts WHERE post_type = ‘attachment’ AND post_mime_type LIKE ‘image/%’ ORDER BY ID DESC” ) ) {

    Change ‘DESC’ to ‘ASC’, as such:

    if ( ! $images = $wpdb->get_results( “SELECT ID FROM $wpdb->posts WHERE post_type = ‘attachment’ AND post_mime_type LIKE ‘image/%’ ORDER BY ID ASC” ) ) {

    Save the file, run the plugin again and this time you should start from product #1 upwards instead of #10000.

    As I said this is a quick fix and you have only one shot – if the script cuts off again (again for whatever reason) then you can’t help but to start from the top again.

    • No mate, you dont have to edit anything.. I got disconnect when running the script, all I have to do is wait a few minutes, it auto resume and continous running without touching anything

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  30. Hi there!

    First of all, thanks for sharing this plugin to us. However, I’ve been having problems with it since Tuesday. The images are not loading properly in my three most recent blog posts though I never encountered any problem while uploading them. My website is

    I am getting this message in the plugin page: “Warning: This plugin has not been tested with your current version of WordPress.”
    How should I go about this? Thank you very much and more power.


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  32. Doesn’t work with the latest WordPress. Could you please check this out. does the first image looks like it doing all of them but only first image was done

  33. Mine is working fine now. It ended up being a permissions issue… a conflict between “Nobody” and the regular user name. Once the host figured this out, it worked. I have a sneaking suspicion that it may also have had something to do with filling up the storage allowance.

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  36. What resources on the server is this plugin most dependent on? I have a 4core 8gb SSD based VPS running only LEMP based WordPress site, and the regeneration of thumbnails is extremely slow ~5s each.

    I’m no server expert, but I’ve increased PHP memory, post size, max_vars, MariaDB limits, etc, and the regeneration is still so slow.

    Or is ~5s per image normal, and I just need to let this run for days to complete all the regenerations?

    • If you have that kind of access to your site, then I recommend that you SSH into your site and do the regeneration using WP-CLI, a command line interface for WordPress. It supports regenerating all of your thumbnails:

      Installation is easy and instructions can be found here:

      It’ll go a lot faster than my plugin because you won’t have the overhead of the HTTP request for each image, nor will WordPress have to be loaded each and every time. To avoid running out of memory, my plugin regenerates each image one at a time with a separate AJAX request.

      It’ll still be CPU intensive as you’re resizing a bunch of images, but with less overhead it’ll go much, much faster.

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  38. hey. all my images on my site are messed up.

    i regenerated all my thumbnail but sadly it doesnt update my previous post and it doesnt even shown in my media library.

    but all generated images can be found in FTP > UPLOAD

    whats going on here please advise

  39. Love this plugin 🙂 I just wonder if it would be possible to show the regenerate button on the feature image page as that could save me some time going back and forth.

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  41. hi,
    thanks for developing this plugin; unfortunately your plugin was working fine for me, but after installing woocommerce I went into media setting to change the details and regenerate the thumbnails size and I got this error:
    function () {if(h){var d=h.length;!function f(b){m.each(b,function(b,c){var d=m.type(c);”function”===d?a.unique&&k.has(c)||h.push(c):c&&c.length&&”string”!==d&&f(c)})}(arguments),b?e=h.length:c&&(g=d,j(c))}return this;}


    • That super annoying bug happens when the AJAX endpoint returns something other than just JSON. In short, a PHP warning or error or something is being outputted and causing my plugin to not be able to parse the response.

  42. I think I’ve seen that before. I believe it turned out to be a php permissions error with the image processor that manifests as a JavaScript file beg returned. But there error is actually in a php process somewhere.

  43. Not sure if this plugin’s still being maintained or not (I don’t want to install Jetpack for, well, reasons). But if so, I’m getting a deprecation error when running it on PHP 7.

    > Deprecated: Methods with the same name as their class will not be constructors in a future version of PHP; RegenerateThumbnails has a deprecated constructor in /path/to/wp/wp-content/plugins/regenerate-thumbnails/regenerate-thumbnails.php on line 31

    PHP 7 might still be in release candidate stage, but it’s still an error that’s easy to future-proof: simply rename the constructor function to the correct `__construct` instead of the class’s name. =)

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