diff --git a/src/lerobot/datasets/v21/convert_stats.py b/src/lerobot/datasets/v21/convert_stats.py
index 462781c15..4effe9dd9 100644
--- a/src/lerobot/datasets/v21/convert_stats.py
+++ b/src/lerobot/datasets/v21/convert_stats.py
@@ -45,6 +45,8 @@ def convert_episode_stats(dataset: LeRobotDataset, ep_idx: int):
 
         axes_to_reduce = (0, 2, 3) if ft["dtype"] in ["image", "video"] else 0
         keepdims = True if ft["dtype"] in ["image", "video"] else ep_ft_data.ndim == 1
+        if ft["dtype"] in ["image", "video"] and ep_ft_data.ndim == 3:
+            ep_ft_data = np.expand_dims(ep_ft_data, axis=0)
         ep_stats[key] = get_feature_stats(ep_ft_data, axis=axes_to_reduce, keepdims=keepdims)
 
         if ft["dtype"] in ["image", "video"]:  # remove batch dim