diff --git a/config/default.py b/config/default.py
index 3860ecbcc..aab3fed06 100644
--- a/config/default.py
+++ b/config/default.py
@@ -44,7 +44,6 @@
 NONE_DISPLAY_EXT = ['.tiff', '.tif']
 ALLOWED_IMAGE_EXT = DISPLAY_FILE_EXTENSIONS + NONE_DISPLAY_EXT
 PROCESSED_EXT = '.jpeg'
-IIIF_IMAGE_EXT = ALLOWED_IMAGE_EXT + ['.pdf']
 
 # For system checks
 WRITABLE_PATHS = [
diff --git a/config/iiif.py b/config/iiif.py
index 2562dfc47..574796e07 100644
--- a/config/iiif.py
+++ b/config/iiif.py
@@ -1,3 +1,5 @@
+from config.default import ALLOWED_IMAGE_EXT
+
 IIIF = {
     'activate': False,
     'path': '',
@@ -5,4 +7,6 @@
     'version': 2,
     'conversion': True,
     'compression': 'deflate'  # 'deflate' or 'jpeg'
-}
\ No newline at end of file
+}
+
+IIIF_IMAGE_EXT = ALLOWED_IMAGE_EXT + ['.pdf']
\ No newline at end of file