Title: wordpress thumbnail function not working
Last modified: August 20, 2016

---

# wordpress thumbnail function not working

 *  Resolved [ezhil](https://wordpress.org/support/users/ezhil/)
 * (@ezhil)
 * [15 years ago](https://wordpress.org/support/topic/wordpress-thumbnail-function-not-working/)
 * hi,
    i was working with thumbnail image for my theme. i added the code
 *     ```
       if ( function_exists( 'add_theme_support' ) ) {
         add_theme_support( 'post-thumbnails' );
       }
       ```
   
 * in my function.php and then tried to call the function
    `<?php the_post_thumbnail();?
   >` in my theme’s loop but it returned error stating undefined function I just
   tested the same post image in my post( i called the thumbnail size of the image)
   it showed the cropped image for 150 * 150, but if i change the media setting 
   to change thumbnail image size it doesn’t change ( it still remain 150*150 ).
 * help me out guys.

Viewing 1 replies (of 1 total)

 *  Thread Starter [ezhil](https://wordpress.org/support/users/ezhil/)
 * (@ezhil)
 * [14 years, 11 months ago](https://wordpress.org/support/topic/wordpress-thumbnail-function-not-working/#post-2123447)
 * Iam nuts,
    I need to mention the parameter `<?php the_post_thumbnail('thumbnail');?
   >`

Viewing 1 replies (of 1 total)

The topic ‘wordpress thumbnail function not working’ is closed to new replies.

## Tags

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

 * 1 reply
 * 1 participant
 * Last reply from: [ezhil](https://wordpress.org/support/users/ezhil/)
 * Last activity: [14 years, 11 months ago](https://wordpress.org/support/topic/wordpress-thumbnail-function-not-working/#post-2123447)
 * Status: resolved

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