diff --git a/avatar/models.py b/avatar/models.py
index 5bc3a52..0657b6c 100644
--- a/avatar/models.py
+++ b/avatar/models.py
@@ -103,7 +103,7 @@ 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()