diff --git a/matrix/element-web/README.md b/matrix/element-web/README.md
index 08f2d4f..dddaf0b 100644
--- a/matrix/element-web/README.md
+++ b/matrix/element-web/README.md
@@ -55,6 +55,8 @@ Of course, substitute the correct domain and server name. The `msc3575.proxy`
 is for SSS and may not be necessary. But it won't hurt, so let's just put it
 there.
 
+# Browser notes {#browsernotes}
+
 Element-web runs in the browser, on JavaScript. Yours truly found out that
 running [JShelter](https://jshelter.org/) throws a spanner in the works, so
 you'll have to disable it for the URL you publish Element-web.
@@ -65,3 +67,7 @@ know support for that is on a best effort basis, you might want to consider
 using the "real" Firefox. [Debian packages are
 available](https://support.mozilla.org/en-US/kb/install-firefox-linux#w_install-firefox-deb-package-for-debian-based-distributions-recommended).
 
+Element Web uses "workers", that are not installed in private windows. One
+thing that won't work in a private window, is downloading (i.e. displaying)
+images. If you don't see avatars and get "failed to download" messages, check
+if you're running Element Web in a private window.