diff --git a/galerie/models.py b/galerie/models.py
index c73a3f25..de81a69f 100644
--- a/galerie/models.py
+++ b/galerie/models.py
@@ -118,7 +118,7 @@ class Galerie(models.Model):
 		self.obrazek_set.update(poradi=None)
 		for obrazek in self.obrazek_set.all():
 			try:
-				obr = Image.open(obrazek)
+				obr = Image.open(obrazek.obrazek_velky)
 			except UnidentifiedImageError as e:
 				raise ValueError from e