Ubuntu Linux: Install or Add PHP-GD Support To Apache Web Server

The GD Graphics Library for dynamically manipulating images. You will need to compile PHP with the GD library of image functions for this to work. However. Ubuntu (and Debian) Linux comes with the package called php5-gd. Just type the following command to install this module:
# apt-get install php5-gd
OR
$ sudo apt-get install php5-gd

Sample outputs (from my Debian server)

apt-get install php5-gd
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following extra packages will be installed:
  libgd2-xpm
Suggested packages:
  libgd-tools
The following packages will be REMOVED:
  libgd2-noxpm
The following NEW packages will be installed:
  libgd2-xpm php5-gd
0 upgraded, 2 newly installed, 1 to remove and 7 not upgraded.
Need to get 270 kB of archives.
After this operation, 176 kB of additional disk space will be used.
Do you want to continue [Y/n]? y
Get:1 http://debian.osuosl.org/debian/ squeeze/main libgd2-xpm amd64 2.0.36~rc1~dfsg-5 [231 kB]
Get:2 http://security.debian.org/ squeeze/updates/main php5-gd amd64 5.3.3-7+squeeze9 [39.1 kB]
Fetched 270 kB in 2s (124 kB/s)                                      
dpkg: libgd2-noxpm: dependency problems, but removing anyway as you requested:
 libgvc5 depends on libgd2-noxpm (>= 2.0.36~rc1~dfsg) | libgd2-xpm (>= 2.0.36~rc1~dfsg); however:
  Package libgd2-noxpm is to be removed.
  Package libgd2-xpm is not installed.
(Reading database ... 206928 files and directories currently installed.)
Removing libgd2-noxpm ...
Selecting previously deselected package libgd2-xpm.
(Reading database ... 206919 files and directories currently installed.)
Unpacking libgd2-xpm (from .../libgd2-xpm_2.0.36~rc1~dfsg-5_amd64.deb) ...
Setting up libgd2-xpm (2.0.36~rc1~dfsg-5) ...
Selecting previously deselected package php5-gd.
(Reading database ... 206930 files and directories currently installed.)
Unpacking php5-gd (from .../php5-gd_5.3.3-7+squeeze9_amd64.deb) ...
Processing triggers for libapache2-mod-php5 ...
Reloading web server config: apache2.
Setting up php5-gd (5.3.3-7+squeeze9) ...

Finally, restart the Apache 2 web server, enter:
# /etc/init.d/apache2 restart
Now, you can test your php application.

How do I verify that php5-gd support loaded or not?

Type the following command at a shell prompt:
$ php5 -m | grep -i gd
Sample outputs:

gd

OR
$ php5 -i | grep -i --color gd
OR
$ php -i | grep -i --color gd
Sample outputs:

Additional .ini files parsed => /etc/php5/cli/conf.d/gd.ini,
gd
GD Support => enabled
GD Version => 2.0
gd.jpeg_ignore_warning => 0 => 0
XAUTHORITY => /var/run/gdm3/auth-for-vivek-ruJHl1/database
_SERVER["XAUTHORITY"] => /var/run/gdm3/auth-for-vivek-ruJHl1/database

You can also use the following php code. Create a file called test.php and put in your web server directory i.e. Apache DocumentRoot (such as /var/www):

<?php
  phpinfo();
?>

Run it as follows:
http://your-server-ip/test.php
Look for GD extension.