Title: Generating thumbnails
Last modified: August 19, 2016

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# Generating thumbnails

 *  [peters2007](https://wordpress.org/support/users/peters2007/)
 * (@peters2007)
 * [15 years, 8 months ago](https://wordpress.org/support/topic/generating-thumbnails/)
 * I’m switching my site over from a theme that does not use thumbnails to one that
   does. So for the most recent 15-20 posts, I’m trying to go back and generate 
   the thumbnails. (I’ve already got the appropriate functions in my functions.php
   file.)
 * Problem is, WordPress refuses to generate thumbnails for those posts. It works
   fine if I upload an image and immediately click “Use as featured image”, but 
   if I take an old image – even from a couple of hours earlier – and try to convert
   it into my chosen size of thumbnails, it simply will not generate new thumbnails.
 * Is there any way around this except (1) re-uploaded images all over again, or(
   2) using the Regenerate Thumbnails plugin, which has only one option: to regenerate
   thumbnails for every single one of the images that I’ve ever used in a post on
   my website (i.e. thousands)?

Viewing 1 replies (of 1 total)

 *  [Rev. Voodoo](https://wordpress.org/support/users/rvoodoo/)
 * (@rvoodoo)
 * [15 years, 8 months ago](https://wordpress.org/support/topic/generating-thumbnails/#post-1656138)
 * [http://justintadlock.com/archives/2009/11/16/everything-you-need-to-know-about-wordpress-2-9s-post-image-feature](http://justintadlock.com/archives/2009/11/16/everything-you-need-to-know-about-wordpress-2-9s-post-image-feature)
 * towards the bottom mentions a different plugin…. not sure if it works better?

Viewing 1 replies (of 1 total)

The topic ‘Generating thumbnails’ is closed to new replies.

## Tags

 * [featured image](https://wordpress.org/support/topic-tag/featured-image/)
 * [functions](https://wordpress.org/support/topic-tag/functions/)
 * [thumbnail](https://wordpress.org/support/topic-tag/thumbnail/)

 * In: [Fixing WordPress](https://wordpress.org/support/forum/how-to-and-troubleshooting/)
 * 1 reply
 * 2 participants
 * Last reply from: [Rev. Voodoo](https://wordpress.org/support/users/rvoodoo/)
 * Last activity: [15 years, 8 months ago](https://wordpress.org/support/topic/generating-thumbnails/#post-1656138)
 * Status: not resolved

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