Stricter hiddenImages rule

lib/metadata/policies.js

@@ -970,7 +970,7 @@ var policies = {
         "tool": "phantomas",
         "label": "Hidden images",
         "message": "<p>List of all images that have a display:none property, or one of their parents. These images are loaded by the browser even if they're not visible. You might be able to find a way to lazy-load them, only when they get visible.</p><p>Trackers are an exception, you'd better hide them.</p>",
-        "isOkThreshold": 3,
+        "isOkThreshold": 1,
         "isBadThreshold": 12,
         "isAbnormalThreshold": 30,
         "hasOffenders": true