I've just gotten hopelessly baffled by the whole RotatingSkin for static images. I found the RotatingSkin class in the documentation, but can't find any way of retrieving a pointer to one for a given StaticImage. Skins in general have me kind of confused. Thanks so much for your patience!
MyGUI::StaticImage* image = window->createWidget<MyGUI::StaticImage>("RotatingSkin", MyGUI::IntCoord(150, 150, 100, 150), MyGUI::Align::Default);
MyGUI::ISubWidget* main = image->getSubWidgetMain();
MyGUI::RotatingSkin* rotatingSubskin = main->castType<MyGUI::RotatingSkin>();
Note that "RotatingSkin" used as skin.
Also look at UnitTest_RotatingSkin code: http://redmine.mygui.info/repositories/