diff --git a/zesje/images.py b/zesje/images.py
index be831e18a78fc25224215ae3bc4eb70cddc4a6eb..b4728afceeed645c6b989816b17ba14e1f5e7bb6 100644
--- a/zesje/images.py
+++ b/zesje/images.py
@@ -58,6 +58,9 @@ def fix_corner_markers(corner_keypoints, shape):
         Coordinates of the top left corner marker
     """
 
+    if len(corner_keypoints) == 4:
+        return corner_keypoints
+
     if len(corner_keypoints) < 3:
         raise RuntimeError("Fewer then 3 corner markers found")