This plugin uses the identicon algorithm as implemented in the PHP identicon project library to generate a unique icon for each user on the site who does not have an uploaded icon.

This plugin requires PHP-GD to be installed. There are known problems with the Debian and Ubuntu release of this library, as they don't include the imagerotate() and imageantialias() function calls required for this code to work. Other distributions seem to be fine, and there are workarounds for this on Debian based systems. Such workarounds are outside the scope of support for this plugin, so please don't ask. :)