diff --git a/src/_h5ai/config.js b/src/_h5ai/config.js
index 595b0c5a..54f02963 100644
--- a/src/_h5ai/config.js
+++ b/src/_h5ai/config.js
@@ -100,13 +100,13 @@ H5AI_CONFIG = {
          * Requires PHP on the server.
          * Show thumbnails for image files.
          */
-        "showThumbs": true,
+        "showThumbs": false,
 
         /*
          * Requires PHP on the server.
          * Enable zipped download of selected entries.
          */
-        "zippedDownload": true
+        "zippedDownload": false
     },