One of the biggest issues plaguing Textimage for way too long is the lack of support for PostgreSQL. This has now, hopefully, changed.

I've just recently made two commits related to this issue, and can confirm that Textimage now works with PgSQL on both Drupal 5 and 6 (in my testing environment at least), and while I haven't yet tested it, I'm confident that it will also work on Drupal 7.

Another major recent change was to increase security, no longer allowing Anonymous users the ability to create random images. However to achieve this tighter security without loss of functionality you will now need to implement your Textimages via either the theme() or CCK methods oppose to the legacy url based method.

For more details on these methods, and to get the latest versions, head over to the project page at:
http://drupal.org/project/textimage