--- fitdump.c
+++ fitdump.c
@@ -37,7 +37,7 @@
 
 static char *out_dir = "./fit-dump";
 static char *out_name = "image.its";
-static char *out_file_mask = "image_%03u.bin";
+static char *out_file_mask = "image.%03u";
 static char *nodename_file_mask = "%s.image";
 static int out_file_index = 0;
 static char out_file_name[PATH_MAX];