I am trying to install Drupal 8.0.5 on Apache 2.4.6 on CentOS 7, with PHP 5.6.19. But in the web GUI for finalizing the Drupal installation, I get a problem on the requirements page. It says "PHP extensions disabled. Drupal requires you to enable the PHP extensions in the following list... gd"
I have installed, with yum install these packages: gd, gd-devel, php-gd, php-pdo php-mbstring, php-xml.