diff --git a/app/item/models.py b/app/item/models.py
index 1dfee46..566417f 100644
--- a/app/item/models.py
+++ b/app/item/models.py
@@ -242,7 +242,7 @@ class Item(models.Model):
 
     def preview(self):
         from django.utils.html import escape, mark_safe
-        if "thumbnail" in self.data:
+        if self.data.get("thumbnail"):
             return mark_safe('<img src="%s" style="max-width:100%%" />' % escape(self.data["thumbnail"]))
         return ""