diff --git a/renku/domain_model/dataset.py b/renku/domain_model/dataset.py
index 59dd3deae0..e327ec0109 100644
--- a/renku/domain_model/dataset.py
+++ b/renku/domain_model/dataset.py
@@ -180,7 +180,7 @@ class ImageObject(Slots):
 
     id: str
     content_url: str
-    position: str
+    position: int
 
     def __init__(self, *, content_url: str, id: str, position: int):
         id = get_path(id)
@@ -656,6 +656,8 @@ def update_metadata_from(self, other: "Dataset", exclude=None):
         # and not match the SHACL definition for Renku. This cannot be addressed in the dataset
         # providers because the dataset providers do not have access to the dataset ID which is needed
         # for setting the dataset image ID.
+        if not isinstance(self.images, list):
+            return
         for image_ind in range(len(self.images)):
             self.images[image_ind].id = ImageObject.generate_id(self.id, self.images[image_ind].position)