ImageType
Describes the image data representation used by a class@Gtk.Image.
If you want to get the image from the widget, you can only get the currently-stored representation; for instance, if the gtk_image_get_storage_type() returns %GTK_IMAGE_PAINTABLE, then you can call gtk_image_get_paintable().
For empty images, you can request any storage type (call any of the "get" functions), but they will all return null values.