To provide extensibility, the functionality for loading and saving bitmap formats is not implemented in the wxBitmap class, but in a number of handler classes, derived from wxBitmapHandler. There is a static list of handlers which wxBitmap examines when a file load/save operation is requested. Some handlers are provided as standard, but if you have special requirements, you may wish to initialise the wxBitmap class with some extra handlers which you write yourself or receive from a third party.
To add a handler object to wxBitmap, your application needs to include the header which implements it, and then call the static function wxBitmap::AddHandler.
Note: bitmap handlers are not implemented on all platforms, and new ones rarely need
to be implemented since wxImage can be used for loading most formats, as noted earlier.