diff --git a/ext/gd/gd.c b/ext/gd/gd.c
index 0c6053b7848..05ab6551c06 100644
--- a/ext/gd/gd.c
+++ b/ext/gd/gd.c
@@ -1200,6 +1200,9 @@ PHP_MINIT_FUNCTION(gd)
 	REGISTER_LONG_CONSTANT("IMG_EFFECT_NORMAL", gdEffectNormal, CONST_CS | CONST_PERSISTENT);
 	REGISTER_LONG_CONSTANT("IMG_EFFECT_OVERLAY", gdEffectOverlay, CONST_CS | CONST_PERSISTENT);
 	REGISTER_LONG_CONSTANT("GD_BUNDLED", 1, CONST_CS | CONST_PERSISTENT);
+	REGISTER_LONG_CONSTANT("GD_FLIP_HORINZONTAL", GD_FLIP_HORINZONTAL, CONST_CS | CONST_PERSISTENT);
+	REGISTER_LONG_CONSTANT("GD_FLIP_VERTICAL", GD_FLIP_VERTICAL, CONST_CS | CONST_PERSISTENT);
+	REGISTER_LONG_CONSTANT("GD_FLIP_BOTH", GD_FLIP_BOTH, CONST_CS | CONST_PERSISTENT);
 #else
 	REGISTER_LONG_CONSTANT("GD_BUNDLED", 0, CONST_CS | CONST_PERSISTENT);
 #endif