diff --git a/src/css/main.scss b/src/css/main.scss
index 79370a3..ccac3a3 100644
--- a/src/css/main.scss
+++ b/src/css/main.scss
@@ -111,6 +111,7 @@ figure {
 
   img {
     max-width: 100%;
+    border: 1px solid rgba(100,100,100,.2);
   }
 
   p {