diff --git a/dvdisaster/tools/pngio.h b/dvdisaster/tools/pngio.h
index 36df455..9d392ec 100644
--- a/dvdisaster/tools/pngio.h
+++ b/dvdisaster/tools/pngio.h
@@ -21,6 +21,7 @@
 #define PNGIO_H
 
 #include <png.h>
+#include <zlib.h>
 
 typedef struct
 {  char *name;