diff --git a/etiquette/constants.py b/etiquette/constants.py
index f9aae6e..10d300c 100644
--- a/etiquette/constants.py
+++ b/etiquette/constants.py
@@ -41,7 +41,7 @@ ffmpeg = _load_ffmpeg()
 
 # Database #########################################################################################
 
-DATABASE_VERSION = 19
+DATABASE_VERSION = 20
 DB_VERSION_PRAGMA = f'''
 PRAGMA user_version = {DATABASE_VERSION};
 '''
@@ -254,7 +254,7 @@ ADDITIONAL_MIMETYPES = {
 DEFAULT_DATADIR = '_etiquette'
 DEFAULT_DBNAME = 'phototagger.db'
 DEFAULT_CONFIGNAME = 'config.json'
-DEFAULT_THUMBDIR = 'site_thumbnails'
+DEFAULT_THUMBDIR = 'thumbnails'
 
 DEFAULT_CONFIGURATION = {
     'cache_size': {
@@ -315,6 +315,7 @@ DEFAULT_CONFIGURATION = {
         '_etiquette',
         '_site_thumbnails',
         'site_thumbnails',
+        'thumbnails',
     ],
 
     'file_read_chunk': 2 ** 20,
diff --git a/utilities/database_upgrader.py b/utilities/database_upgrader.py
index 93597b8..e4a497b 100644
--- a/utilities/database_upgrader.py
+++ b/utilities/database_upgrader.py
@@ -654,6 +654,22 @@ def upgrade_18_to_19(photodb):
 
     m.go()
 
+def upgrade_19_to_20(photodb):
+    '''
+    In this version, the thumbnail folder was renamed from "site_thumbnails"
+    to just "thumbnails".
+    '''
+    old = photodb.data_directory.with_child('site_thumbnails')
+    if not old.exists:
+        return
+    new = photodb.data_directory.with_child('thumbnails')
+    if new.exists:
+        if len(new.listdir()) > 0:
+            raise Exception(f'{new.absolute_path} already has items in it.')
+        else:
+            os.rmdir(new.absolute_path)
+    os.rename(old.absolute_path, new.absolute_path)
+
 def upgrade_all(data_directory):
     '''
     Given the directory containing a phototagger database, apply all of the