"GD library is too old. Version 2.0.1 or later is required, and 2.0.28 is strongly recommended."
The libraries installed by Ubuntu were:
$ dpkg -l | grep libgd2 rc libgd2-noxpm 2.0.36~rc1~dfsg-3ubuntu1.9.04.1 GD Graphics Library version 2 (without XPM s ii libgd2-xpm 2.0.36~rc1~dfsg-3ubuntu1.9.04.1 GD Graphics Library version 2 $ dpkg -l | grep php5-gd ii php5-gd 5.2.6.dfsg.1-3ubuntu4.6 GD module for php5The issue here is that Ubuntu does not use the version of GD which is bundled with PHP. See this discussion for more details.
So...some googling around later, I stumbled on this great howtoforge post by patusovniak on "Recompiling PHP5 with bundled support for GD in Ubuntu". It also serves as a good overview of building Ubuntu packages from source. The only observation I have is that after I ran the step
I had to install all .deb packages in /usr/src. So I did
cd /usr/src dpkg -i *.deb
When running phpinfo(), the GD section now looks:
gd GD Support enabled GD Version bundled (2.0.34 compatible) FreeType Support enabled FreeType Linkage with freetype FreeType Version 2.3.11 T1Lib Support enabled GIF Read Support enabled GIF Create Support enabled JPEG Support enabled libJPEG Version 6b PNG Support enabled libPNG Version 1.2.42 WBMP Support enabled XPM Support enabled XBM Support enabled
Hopefully this will be useful to someone out there trying to desperately use a newer version of GD with PHP in Ubuntu...