Unfortunately, Leopard’s PHP installation does not ship with a GD module. If you use this PHP version, Drupal will report that it can’t find a GD library (and no image processing will be performed either). There is a tutorial on the web that explains step by step how to compile GD2 for the stock PHP 5.2.4 that comes with Leopard; however, PHP segfaults after the installation (at least for me).

Fortunately, there is an alternative: Entropy.ch’s PHP 5.2.5 beta package comes with all kinds of modules prepackaged. The folks over at Moodle created a very good step by step instruction for setting that bug.

The drawback: On my (32bit) machine, PHP would refuse to log in (connecting worked fine!) to my (unaltered) database server. At the same time, I was able to connect to it using the mysql CLI binary with the exact same credentials. It turns out that the MySQL Client API in Entropy’s PHP package is somewhat broken on 32bit Intel and PPC (but works fine on 64bit Intel!). After some debugging (checking socks, reviewing debug logs, …) I stumbled upon a forum post which provides a quick fix for this issue: Just copy over the stock Leopard MySQL Client libs to the new PHP installation and you’re done.