diff --git a/web/assets/agaric-blue.scss b/web/assets/agaric-blue.scss
index fdb0af9..1ad7f07 100755
--- a/web/assets/agaric-blue.scss
+++ b/web/assets/agaric-blue.scss
@@ -43,6 +43,10 @@ section.has-light-background {
 	}
 }
 
+.reveal section img.plain {
+  background: none;
+}
+
 .reveal blockquote {
   border: dashed 5px #823a69;
 }