diff --git a/.gitignore b/.gitignore
index 74eebb96b..624ce100c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -29,4 +29,4 @@
 nginx/default.conf
 
 #macOS
-.DS_Store
+**/.DS_Store
diff --git a/bookwyrm/templatetags/utilities.py b/bookwyrm/templatetags/utilities.py
index 1be660496..bcb1ec4ec 100644
--- a/bookwyrm/templatetags/utilities.py
+++ b/bookwyrm/templatetags/utilities.py
@@ -54,7 +54,7 @@ def truncatepath(value, arg):
 
 
 @register.simple_tag(takes_context=False)
-def get_book_cover_thumbnail(book, size, ext):
+def get_book_cover_thumbnail(book, size="medium", ext="jpg"):
     """Returns a book thumbnail at the specified size and extension, with fallback if needed"""
     try:
         cover_thumbnail = getattr(book, "cover_bw_book_%s_%s" % (size, ext))