Title: thumbnails – cannot modify heading error
Last modified: August 19, 2016

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# thumbnails – cannot modify heading error

 *  Resolved [oldbag66](https://wordpress.org/support/users/oldbag66/)
 * (@oldbag66)
 * [16 years, 2 months ago](https://wordpress.org/support/topic/thumbnails-cannot-modify-heading-error/)
 * Hi, just followed the post thumbnail images tutorial [here](http://markjaquith.wordpress.com/2009/12/23/new-in-wordpress-2-9-post-thumbnail-images/),
   it all works – except though when i add the thumbnail in admin it goes to a page
   with this error:
 * **Warning: Cannot modify header information – headers already sent by (output
   started at /var/www/vhosts/bradwaters.com/httpdocs/wp-content/themes/bradzz/functions.
   php:6) in /var/www/vhosts/bradwaters.com/httpdocs/wp-includes/pluggable.php on
   line 868**
 * any ideas ?

Viewing 9 replies - 1 through 9 (of 9 total)

 *  Thread Starter [oldbag66](https://wordpress.org/support/users/oldbag66/)
 * (@oldbag66)
 * [16 years, 2 months ago](https://wordpress.org/support/topic/thumbnails-cannot-modify-heading-error/#post-1401839)
 * p.s. it does actually post the thumbnail properly so it does work..BUT i dont
   want that error!
 *  [Rev. Voodoo](https://wordpress.org/support/users/rvoodoo/)
 * (@rvoodoo)
 * [16 years, 2 months ago](https://wordpress.org/support/topic/thumbnails-cannot-modify-heading-error/#post-1401841)
 * do you have any blank space at the top of your functions.php file?
 * the very first line should be `<?php` right at the top
 * if that’s not the issue, throw up your functions.php in a [pastebin](http://wordpress.pastebin.com/)
 * and also maybe a link to your site, in case viewing your source can help us
 *  Thread Starter [oldbag66](https://wordpress.org/support/users/oldbag66/)
 * (@oldbag66)
 * [16 years, 2 months ago](https://wordpress.org/support/topic/thumbnails-cannot-modify-heading-error/#post-1401848)
 * just made sure no gaps, its in pastebin, i dont know that much about the functions
   file, hopefully you can help!
 * [http://wordpress.pastebin.com/KJXaAt9i](http://wordpress.pastebin.com/KJXaAt9i)
 *  Thread Starter [oldbag66](https://wordpress.org/support/users/oldbag66/)
 * (@oldbag66)
 * [16 years, 2 months ago](https://wordpress.org/support/topic/thumbnails-cannot-modify-heading-error/#post-1401849)
 * site: [http://www.bradwaters.com/category/news/creative-work/](http://www.bradwaters.com/category/news/creative-work/)
 *  [nouveller](https://wordpress.org/support/users/nouveller/)
 * (@nouveller)
 * [16 years, 2 months ago](https://wordpress.org/support/topic/thumbnails-cannot-modify-heading-error/#post-1401855)
 * You might want to look for white space issues in **/wp-includes/pluggable.php**
 * It’s a common error: [http://lmgtfy.com/?q=wordpress+pluggable+error](http://lmgtfy.com/?q=wordpress+pluggable+error)
 *  Thread Starter [oldbag66](https://wordpress.org/support/users/oldbag66/)
 * (@oldbag66)
 * [16 years, 2 months ago](https://wordpress.org/support/topic/thumbnails-cannot-modify-heading-error/#post-1401859)
 * pluggable didnt have a closing php tag at the very end, going to try that `?>`
 *  Thread Starter [oldbag66](https://wordpress.org/support/users/oldbag66/)
 * (@oldbag66)
 * [16 years, 2 months ago](https://wordpress.org/support/topic/thumbnails-cannot-modify-heading-error/#post-1401863)
 * it worked! – thanks all
 *  [Rev. Voodoo](https://wordpress.org/support/users/rvoodoo/)
 * (@rvoodoo)
 * [16 years, 2 months ago](https://wordpress.org/support/topic/thumbnails-cannot-modify-heading-error/#post-1401867)
 * EDIT-nevermind my post here, you got it!
 *     ```
       <?php
       if ( function_exists( 'add_theme_support' ) ) { // Added in 2.9
       	add_theme_support( 'post-thumbnails' );
       	set_post_thumbnail_size( 70, 70, true ); // Normal post thumbnails
       }
       ?>
       ```
   
 * here’s how I do it, which works…. the if function stuff isn’t necessary….just
   keeps my theme safe for older WP versions if I release it….. If it’s not an issue
   with pluggable.php, see if maybe this code works any better
 *  Thread Starter [oldbag66](https://wordpress.org/support/users/oldbag66/)
 * (@oldbag66)
 * [16 years, 2 months ago](https://wordpress.org/support/topic/thumbnails-cannot-modify-heading-error/#post-1401869)
 * ah yes that tidys that up will do, thanks for your speedy help : )

Viewing 9 replies - 1 through 9 (of 9 total)

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## Tags

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

 * In: [Fixing WordPress](https://wordpress.org/support/forum/how-to-and-troubleshooting/)
 * 9 replies
 * 3 participants
 * Last reply from: [oldbag66](https://wordpress.org/support/users/oldbag66/)
 * Last activity: [16 years, 2 months ago](https://wordpress.org/support/topic/thumbnails-cannot-modify-heading-error/#post-1401869)
 * Status: resolved

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