diff --git a/nbsite/gallery/thumbnailer.py b/nbsite/gallery/thumbnailer.py
index 2cd9c0a1..a9d22c90 100644
--- a/nbsite/gallery/thumbnailer.py
+++ b/nbsite/gallery/thumbnailer.py
@@ -14,6 +14,10 @@ def thumbnail(obj, basename):
     import os
     if isinstance(obj, Dimensioned) and not os.path.isfile(basename+'.png'):
         Store.renderers[Store.current_backend].save(obj, basename, fmt='png')
+    elif 'panel' in sys.modules:
+        from panel.viewable import Viewable
+        if isinstance(obj, Viewable) and not os.path.isfile(basename+'.png'):
+            obj.save(basename+'.png')
     return obj
 
 
diff --git a/setup.py b/setup.py
index f307646d..39bb6d34 100644
--- a/setup.py
+++ b/setup.py
@@ -62,6 +62,7 @@ def get_setup_version(root, reponame):
         'notebook',
         'sphinx',
         'beautifulsoup4',
+        'tornado <6'
     ],
     extras_require= {
         'refman':[