Last week I managed to move both of my WordPress blogs onto Linode with just a a few easily solved issues with permissions and file ownership.
One hurdle I did get stuck at however was WordPress being unable to create different size images in the Media Library on upload. This meant that each image was only available to use in posts and pages at full size. This was fine if I wanted to use full size images but if a gallery of thumbnails was required WordPress would do the next best thing and present an array of full size images resized as thumbnails, this in unacceptable in terms of page load speed etc.
So, why does a WordPress install on my new server not create thumbnail and medium size images on upload to the media library?
The answer turned out to be lack of PHP-GD Support on my Apache web server. GD Extends PHP to support image manipulation, in this case allowing WordPress to create different size images on upload into the media library.
The solution is simple, if you’re on a Debian based server like Ubuntu run the following in a shell and restart Apache.
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# Install php5-gd sudo apt-get install php5-gd # Restart Apache service apache2 restart # Verify installation $ php5 -m | grep -i gd
And there was me convinced it was a permissions issue. Taxi for Coleman.