Index: Modules/imageop.c
===================================================================
--- Modules/imageop.c	(revision 67215)
+++ Modules/imageop.c	(working copy)
@@ -590,10 +590,10 @@
 	if ( !PyArg_ParseTuple(args, "s#ii", &cp, &len, &x, &y) )
 		return 0;
 
-	if ( !check_multiply_size(len*4, x, "x", y, "y", 4) )
+	if ( !check_multiply_size(len, x, "x", y, "y", 4) )
 		return 0;
 	nlen = x*y;
-	if ( !check_multiply(nlen, x, y) )
+	if ( !check_multiply(nlen * 4, x, y) )
 		return 0;
 
 	rv = PyString_FromStringAndSize(NULL, nlen);