diff --git a/contrib/static/krane.css b/contrib/static/krane.css
index 5132fb6..56f96cb 100644
--- a/contrib/static/krane.css
+++ b/contrib/static/krane.css
@@ -441,3 +441,7 @@ background-repeat: repeat;
     white-space: pre-line;
     word-break: break-word;
 }
+
+#captcha_img {
+    background-color: white;
+}