diff --git a/sigal/gallery.py b/sigal/gallery.py
index d8a2351..926c4a0 100644
--- a/sigal/gallery.py
+++ b/sigal/gallery.py
@@ -235,6 +235,9 @@ class Image(Media):
         super().__init__(filename, path, settings)
         imgformat = settings.get('img_format')
 
+        # Register all formats
+        PILImage.init()
+
         if imgformat and PILImage.EXTENSION[self.src_ext] != imgformat.upper():
             # Find the extension that should match img_format
             extensions = {v: k for k, v in PILImage.EXTENSION.items()}
@@ -492,7 +495,7 @@ class Album:
             def sort_key(s):
                 sort_attr = albums_sort_attr
                 if not isinstance(sort_attr,list):
-                    sort_attr = [sort_attr] 
+                    sort_attr = [sort_attr]
 
                 album = self.gallery.albums[join(root_path, s)]
 
diff --git a/tox.ini b/tox.ini
index 164d182..6c2e08b 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,19 +1,19 @@
 [tox]
-envlist = py{38,39,310}-pillow{71,80,-latest},pypy3,check
+envlist = py{38,39,310}-pillow{80,90,-latest},pypy3,check
 skip_missing_interpreters = true
 isolated_build = true
 
 [gh-actions]
 python =
-    3.8: py38-pillow71, check
-    3.9: py39-pillow80
+    3.8: py38-pillow80, check
+    3.9: py39-pillow90
     3.10: py310-pillow-latest
     pypy3: pypy3
 
 [testenv]
 deps =
-    pillow71: Pillow==7.1.0
-    pillow80: Pillow==8.0.0
+    pillow80: Pillow==8.0.1
+    pillow90: Pillow==9.0.1
 extras =
     all
     tests