if (g_signal_handlers_disconnect_by_func(G_OBJECT(il), (GCallback)image_load_area_cb, old_data))
g_signal_connect(G_OBJECT(il), "area_ready", (GCallback)image_load_area_cb, data);
if (g_signal_handlers_disconnect_by_func(G_OBJECT(il), (GCallback)image_load_area_cb, old_data))
g_signal_connect(G_OBJECT(il), "area_ready", (GCallback)image_load_area_cb, data);