diff --git a/avatar/models.py b/avatar/models.py
index 3557410..c64b21b 100644
--- a/avatar/models.py
+++ b/avatar/models.py
@@ -116,7 +116,7 @@ class Avatar(models.Model):
                 else:
                     diff = int((h - w) / 2)
                     image = image.crop((0, diff, w, h - diff))
-                if image.mode != "RGB":
+                if image.mode not in ("RGB", "RGBA"):
                     image = image.convert("RGB")
                 image = image.resize((size, size), settings.AVATAR_RESIZE_METHOD)
                 thumb = six.BytesIO()
diff --git a/tests/data/django.png b/tests/data/django.png
new file mode 100644
index 0000000..82474cb
Binary files /dev/null and b/tests/data/django.png differ
diff --git a/tests/data/django_pony_cmyk.jpg b/tests/data/django_pony_cmyk.jpg
new file mode 100644
index 0000000..2712f77
Binary files /dev/null and b/tests/data/django_pony_cmyk.jpg differ
diff --git a/tests/tests.py b/tests/tests.py
index 64db82b..07c9f46 100644
--- a/tests/tests.py
+++ b/tests/tests.py
@@ -3,6 +3,7 @@ import os.path
 from django.contrib.admin.sites import AdminSite
 from django.test import TestCase
 from django.core.urlresolvers import reverse
+from django.test.utils import override_settings
 
 from avatar.admin import AvatarAdmin
 from avatar.conf import settings
@@ -164,3 +165,16 @@ class AvatarTests(TestCase):
     # def testChangePrimaryAvatar
     # def testDeleteThumbnailAndRecreation
     # def testAutomaticThumbnailCreation
+
+    @override_settings(AVATAR_THUMB_FORMAT='png')
+    def testAutomaticThumbnailCreationRGBA(self):
+        upload_helper(self, "django.png")
+        avatar = get_primary_avatar(self.user)
+        image = Image.open(avatar.avatar.storage.open(avatar.avatar_name(settings.AVATAR_DEFAULT_SIZE), 'rb'))
+        self.assertEqual(image.mode, 'RGBA')
+
+    def testAutomaticThumbnailCreationCMYK(self):
+        upload_helper(self, "django_pony_cmyk.jpg")
+        avatar = get_primary_avatar(self.user)
+        image = Image.open(avatar.avatar.storage.open(avatar.avatar_name(settings.AVATAR_DEFAULT_SIZE), 'rb'))
+        self.assertEqual(image.mode, 'RGB')