diff --git a/lib/Alchemy/Phrasea/Controller/Prod/Tooltip.php b/lib/Alchemy/Phrasea/Controller/Prod/Tooltip.php
index a79a2e394b..6cc8359da3 100644
--- a/lib/Alchemy/Phrasea/Controller/Prod/Tooltip.php
+++ b/lib/Alchemy/Phrasea/Controller/Prod/Tooltip.php
@@ -103,12 +103,10 @@ class Tooltip implements ControllerProviderInterface
 
     public function displayPreview(Application $app, $sbas_id, $record_id)
     {
-        $record = new \record_adapter($app, $sbas_id, $record_id);
-
-        return $app['twig']->render(
-                'prod/Tooltip/Preview.html.twig'
-                , array('record'      => $record, 'not_wrapped' => true)
-        );
+        return $app['twig']->render('prod/Tooltip/Preview.html.twig', array(
+            'record' => new \record_adapter($app, $sbas_id, $record_id),
+            'not_wrapped' => true
+        ));
     }
 
     public function displayCaption(Application $app, $sbas_id, $record_id, $context)
diff --git a/templates/web/prod/Tooltip/Tooltip.html.twig b/templates/web/prod/Tooltip/Tooltip.html.twig
index 95eb856df5..5266e93949 100644
--- a/templates/web/prod/Tooltip/Tooltip.html.twig
+++ b/templates/web/prod/Tooltip/Tooltip.html.twig
@@ -1,8 +1,8 @@
-<div class="popover" style="display:block;{% if maxwidth %}max-width:{{ maxwidth }}px;{% endif %}{% if width %}width:{{ width }}px;{% endif %}position:relative;">
+<div class="popover" style="display:block;{% if maxwidth is not none %}max-width:{{ maxwidth }}px;{% endif %}{% if width is not none %}width:{{ width }}px;{% endif %}position:relative;">
     <div class="arrow"></div>
     <div class="popover-inner" style="width:auto;">
         <h3 class="popover-title">
-            {% if title %}
+            {% if title is not none %}
                 {{ title }}
             {% endif %}
             <button data-dismiss="modal" class="close tooltip_closer" style="display:none;">×</button>
diff --git a/www/include/jquery.tooltip.js b/www/include/jquery.tooltip.js
index 8ddca19495..2aa9ff24d0 100644
--- a/www/include/jquery.tooltip.js
+++ b/www/include/jquery.tooltip.js
@@ -414,7 +414,7 @@
                 }
 
                 if (resizeImgTips) {
-                    var factor = Math.min((width - 45) / width, (height - 75) / height);
+                    var factor = Math.max(Math.min((width - 45) / width, (height - 75) / height), 1);
                     var imgWidth = Math.round(width * factor);
                     var imgHeight = Math.round(height * factor);