How to fix “PHP Fatal error: Call to undefined function imageconvolution()”

If you’re having trouble with uploading images to WordPress (or other PHP frameworks) and seeing blank spots where images should be, read more to discover a possible fix!

If you’re having trouble with uploading images to WordPress (or other PHP frameworks) and seeing blank spots where images should be, you may need to be sure that LibGD is installed.  Check your Apache or Nginx logs for fatal PHP errors which occur when trying to call undefined functions, for example:

  • PHP Fatal error:  Call to undefined function imageconvolution()
  • PHP Fatal error:  Call to undefined function imagerotate()
  • PHP Fatal error:  Call to undefined function imagecreatefromjpeg()
  • … and other newer GD functions

Here’s an example I gathered from an Nginx log after attempting to rebuild some thumbnails in WordPress using the AJAX Thumbnail Rebuild plugin:

So, let’s fix it!

Even if you’re on the latest Ubuntu 14.04, you may find yourself in a situation where your installed version of PHP was not compiled with libgd, or it is not installed via your package manager.  In that case, it’s easy to install!  For the most part, you shouldn’t have to recompile PHP, so try installing/updating libgd using your package manager.

From the libgd FAQs page:

If you want gd for a PHP application, just do (for Fedora):

Or, for Red Hat Enterprise Linux or CentOS:

Then do:

If your system is Debian based (Debian/Ubuntu/…) then you need to install php5-gd package:

Cluster Fudge: Recipes for WordPress in the Cloud (WordCamp Austin 2014)

About a month ago, I gave a talk at WordCamp Austin 2014 about running enterprise-class WordPress in clustered, cloud-hosted environments. Thanks to all who attended, and for your great questions! While it was standing room only for “Cluster Fudge: Recipes for WordPress in the Cloud”, I hope that everyone who wanted to get in was able to see my presentation.

I’d love to keep the discussion going, so feel free to offer your own best practices and tips for success in running WordPress in the cloud at scale! You can leave comments at the bottom of the page.

About a month ago, I gave a talk at WordCamp Austin 2014 about running enterprise-class WordPress in clustered, cloud-hosted environments.  Thanks to all who attended, and for your great questions! While it was standing room only for “Cluster Fudge: Recipes for WordPress in the Cloud“, I hope that everyone who wanted to get in was able to see my presentation.

I’d love to keep the discussion going, so feel free to offer your own best practices and tips for success in running WordPress in the cloud at scale!  You can leave comments at the bottom of the page.

Overview

Your self-hosted WordPress site is quickly growing in popularity and page views. Or maybe you want to get away from that costly enterprise CMS currently on your plate and adopt a delectable, open-source platform. There are many reasons you might need the performance and redundancy of a clustered server solution, and I’ll show you how to mix up the ingredients needed to throw together a successful cloud-hosted WordPress environment that’s right for you.

We’ll talk about common multi-server configurations, from cheap and quick for the cost-conscious business, to robust and complex for the high level of control an enterprise demands. You will leave with a better knowledge of which web server makes sense for your requirements, and learn some tips and tricks to better caching without sacrificing the dynamic nature of WordPress.

Downloadable code snippets and example config files will help get you started in your own cloud environment.

Example Code and Configuration Files

Visit my GitHub repo for examples of server configuration files optimized for WordPress, and PDF versions of my slides with speaker notes.

Slides

If you missed it, you can view my slides embedded from SlideShare below.