Less contrast gallery image border in MD style

boards/static/css/md/base_page.css

@@ -446,7 +446,7 b' li {'
 }
 
 .gallery_image {
-    border: solid 1px;
+    border: solid 1px #999;
     margin: 0.5ex;
     text-align: center;
     padding: 1ex;