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;