Hello,
sometimes you need to generate Custom POI for your Garmin from the commandline. Free GpsBabel is too simple for this, it not know all features like Garmin PoiLoader. Try new freeware Windows commandline tool GpiGen instead!
It know nearly same features like PoiLoader, using GPX+BMP source files in the same format like PoiLoader, and it is faster! And you can easily integrate it into your batch files or integrate it with your favourite geocaching application.
Cheers!