diff --git a/themes/blueprint/js/preview.js b/themes/blueprint/js/preview.js
index e223507704762472c298e08fc2708d6e1cfc581a..70871aa87161f4da88e89e5de624b64f2f2bfb87 100644
--- a/themes/blueprint/js/preview.js
+++ b/themes/blueprint/js/preview.js
@@ -28,7 +28,10 @@ function getHTPreviews(skeys) {
 }
 
 function applyPreviewUrl($link, url) {
+    // Update the preview button:
     $link.attr('href', url).show();
+
+    // Update associated record thumbnail, if any:
     $link.parents('.result,.record')
         .find('img.summcover,img.recordcover')
         .parents('a').attr('href', url);
diff --git a/themes/bootstrap/js/preview.js b/themes/bootstrap/js/preview.js
index c1eed9fd20e0042addaa8d65654670b76a35294b..087581fe6f62ef7548903f50bd21326773484c97 100644
--- a/themes/bootstrap/js/preview.js
+++ b/themes/bootstrap/js/preview.js
@@ -28,7 +28,10 @@ function getHTPreviews(skeys) {
 }
 
 function applyPreviewUrl($link, url) {
+    // Update the preview button:
     $link.attr('href', url).show();
+
+    // Update associated record thumbnail, if any:
     $link.parents('.result,.record')
         .find('img.img-polaroid')
         .parents('a').attr('href', url);