diff --git a/caver/schema/schema.json b/caver/schema/schema.json
index df059bd..cedf90a 100644
--- a/caver/schema/schema.json
+++ b/caver/schema/schema.json
@@ -135,7 +135,7 @@
                 },
                 {
                     "type": "string",
-                    "pattern": "^*.bmp$"
+                    "pattern": "^.*\\.bmp$"
                 }
             ],
             "default": null