If you wish to expand on ImageAPI add a new wrapper function to
imageapi.module. Do any common preprocessing for all underlying layers in the
wrapper function, then invoke the driver. Pay heed to the function naming in
ImageAPI and ImageAPI GD. If the toolkit changes the size of an image it must
update the $image->info['width'] and $image->info['height'] variables. All
ToolKit functions should return TRUE on success and FALSE on failure.