diff --git a/web/data/config.html b/web/data/config.html
index 3059dc7..f95ecee 100644
--- a/web/data/config.html
+++ b/web/data/config.html
@@ -55,6 +55,12 @@
change only, and does not hide the uploaders actual identity.
+
Exclusions can be specified, zero or more arbitrary strings. If any
+ file matches one of those strings then it will not be uploaded. This is most
+ often used if you use software (like Steam) which automatically creates thumbnails
+ in the same directory as the screenshots.
+