diff --git a/xmodule/static/css-builtin-blocks/HtmlBlockDisplay.css b/xmodule/static/css-builtin-blocks/HtmlBlockDisplay.css
index b89bb3c8c7ed..0896a814a210 100644
--- a/xmodule/static/css-builtin-blocks/HtmlBlockDisplay.css
+++ b/xmodule/static/css-builtin-blocks/HtmlBlockDisplay.css
@@ -222,6 +222,7 @@
 .xmodule_display.xmodule_HtmlBlock img,
 .xmodule_display.xmodule_StaticTabBlock img {
     max-width: 100%;
+    height: auto;
 }
 
 .xmodule_display.xmodule_AboutBlock pre,