diff --git a/css/preflight.css b/css/preflight.css
index 3e17e71ab..92bdc2108 100644
--- a/css/preflight.css
+++ b/css/preflight.css
@@ -577,7 +577,7 @@ button,
 
 textarea { resize: vertical; }
 
-img { max-width: 100%; }
+img { max-width: 100%; height: auto; }
 
 button, input, optgroup, select, textarea { font-family: inherit; }