from w w w.cgpsmapper.com

the routable version allow you to create routable maps without limitations:
Global indexing - find functionality now working in old and new receivers (note: at the moment before using map in GPS, it has to be processed by MapSource to convert global index into GPS format)
Find fastest or shortest route
Support for all kinds of restrictions
Allows routing within GPS or with Garmin MapSource software
Create big routable maps built from several parts
Use all the features of the Pro version

the basic version of the program allows to create basic maps which are compatible with Garmin GPS receivers - If you want to create more advanced maps with POI search functionality - you should check the pro version (personal)
I dont think to convert an already made IMG you require the routable personal version