The WordPress plugin Imsanity requires GD to work.
This is the error message you might get:
Oh Snap! Imsanity was unable to resize this image for the following reason: ‘No editor could be selected.’ . If you continue to see this error message, you may need to either install missing server components or disable the Imsanity plugin. If you think you have discovered a bug, please report it on the Insanity support forum
Install GD on Ubuntu is a straight forward task
To check if Ubuntu already has GD installed:
php7.0 -m | grep -i gd
If GD is installed then it should print:
gd
If there is no answer, then you should install GD with this command:
sudo apt-get install php7.0-gd
Reboot the server or at least restart apache to make GD start working.
To restart the server:
sudo reboot now
To reboot apache:
sudo service apache2 restart
Detailed information about GD
To get mor info about your GD installation type this command:
php7.0 -i | grep -i --color gd
OR
php -i | grep -i --color gd
The output could look like this:
/etc/php/7.0/cli/conf.d/20-gd.ini, gd GD Support => enabled GD headers Version => 2.1.1 GD library Version => 2.1.1 gd.jpeg_ignore_warning => 0 => 0
Alternative solution to verify that GD is installed
Create a file called test.php with the following content:
<?php phpinfo(); ?>
Place test.php your web server root directory such as
/var/www/
Run test.php as follows:
http://your-domain/test.php
Look for GD extension in the long page that is displayed about you PHP configuration.