diff --git a/assets/css/default.css b/assets/css/default.css
index 493bcb7c..8a9a0c1a 100644
--- a/assets/css/default.css
+++ b/assets/css/default.css
@@ -89,6 +89,7 @@ div.thumbnail {
 img.thumbnail {
   position: absolute;
   width: 100%;
+  height: 100%;
   left: 0;
   top: 0;
 }