diff --git a/extra/images/png/png.factor b/extra/images/png/png.factor
index 90ebfe2382..2c4ff948f9 100644
--- a/extra/images/png/png.factor
+++ b/extra/images/png/png.factor
@@ -7,6 +7,7 @@ io.encodings.binary io.encodings.string io.streams.byte-array
 io.streams.throwing kernel locals math math.bitwise
 math.functions math.order math.ranges sequences sorting ;
 QUALIFIED-WITH: bitstreams bs
+QUALIFIED: math
 IN: images.png
 
 SINGLETON: png-image