This is the great package to have!
However this package seems like Images :: Image_Driver by Jesper Veggerby (http://pear.php.net/pepr/pepr-proposal-show.php?id=212) ,but why you do not use GD? I think doesn't big problem for user to install GD extension (if you need it load it, except PHP doesn't support it). I see Image_Driver does not support XBM image yet, would be good if you work together with Jesper.
Thank you for your comment!
Main goal of the package is to give user a tool to work with graphics in absence of the GD library.
In my personal practice, I've incountered situtuations where some web hosting providers had not
installed the library and used safe mode for some reason, which makes it impossible to use dl () function.