Integers are specified as "i" and not as "d".
diff --git a/Modules/rgbimgmodule.c b/Modules/rgbimgmodule.c
index 86ee71c..4421f5d 100644
--- a/Modules/rgbimgmodule.c
+++ b/Modules/rgbimgmodule.c
@@ -723,7 +723,7 @@
 {
     int order, oldorder;
 
-    if (!getargs(args, "d", &order))
+    if (!getargs(args, "i", &order))
 	return NULL;
     oldorder = reverse_order;
     reverse_order = order;