diff --git a/models/site.rb b/models/site.rb
index 8d8a0112..1931d817 100644
--- a/models/site.rb
+++ b/models/site.rb
@@ -1725,7 +1725,7 @@ class Site < Sequel::Model
 
   def thumbnail_url(path, resolution)
     path[0] = '' if path[0] == '/'
-    "#{THUMBNAILS_URL_ROOT}/#{sharding_dir}/#{values[:username]}/#{path}.#{resolution}.webp"
+    "#{THUMBNAILS_URL_ROOT}/#{sharding_dir}/#{values[:username]}/#{self.class.escape_path(path)}.#{resolution}.webp"
   end
 
   def to_rss