diff --git a/agaric/sass/agaric/_layout.flow.scss b/agaric/sass/agaric/_layout.flow.scss
index e5b161e..7140091 100644
--- a/agaric/sass/agaric/_layout.flow.scss
+++ b/agaric/sass/agaric/_layout.flow.scss
@@ -103,6 +103,13 @@
   }
 }
 
+// Center-align standalone image paragraphs.
+.flow_middle > img {
+  display: block;
+  margin-left: auto;
+  margin-right: auto;
+}
+
 // Adding this so the comment box at the bottom isn't unnaturally small.
 // This perhaps should be more precisely targeted, or more generally.