New API in gtkmm 2.14

Member Gdk::Pixbuf::create_from_stream (const Glib::RefPtr< Gio::InputStream > & stream, const Glib::RefPtr< Gio::Cancellable > & cancellable)

Member Gdk::Pixbuf::create_from_stream_at_scale (const Glib::RefPtr< Gio::InputStream > & stream, int width, int height, bool preserve_aspect_ratio, const Glib::RefPtr< Gio::Cancellable > & cancellable)