diff --git a/user.js b/user.js
index d8c26a4..d768202 100644
--- a/user.js
+++ b/user.js
@@ -529,6 +529,9 @@ user_pref("signon.formlessCapture.enabled", false);
  * [3] https://bugzilla.mozilla.org/show_bug.cgi?id=1319119 ***/
 user_pref("signon.autofillForms.http", false);
 user_pref("security.insecure_field_warning.contextual.enabled", true);
+/* 0911: prevent cross-origin images from triggering an HTTP-Authentication prompt (FF55+)
+ * [1] https://bugzilla.mozilla.org/show_bug.cgi?id=1357835 ***/
+user_pref("network.auth.subresource-img-cross-origin-http-auth-allow", false);
 
 /*** 1000: CACHE [SETUP] ***/
 user_pref("ghacks_user.js.parrot", "1000 syntax error: the parrot's gone to meet 'is maker!");