Update dataset card for image archive release

Add concise documentation for the released trajectory-aligned image archives under images/, including the five ZIP ranges and the sample_index alignment note.

README.md

@@ -43,6 +43,7 @@ The dataset is intended for evaluating embodied navigation, spatial reasoning, a
 | :-- | :-- |
 | `navi_data.pkl` | Canonical PKL file for evaluation. |
 | `viewer-00000-of-00001.parquet` | Parquet representation for the Hugging Face Dataset Viewer table. |
+| `images/` | Trajectory-aligned image release, distributed as five ZIP archives plus a manifest file. |
 
 ## Data Fields
 
@@ -50,7 +51,7 @@ The canonical PKL file stores a list of Python dictionaries. Each sample contain
 
 | Field | Type | Description |
 | :-- | :-- | :-- |
-| `sample_index` | `int` | Case index. |
+| `sample_index` | `int` | Sample index used for viewer browsing and image archive alignment. |
 | `start_pos` | `float[3]` | Initial drone world position `(x, y, z)`. |
 | `start_rot` | `float[3]` | Initial drone orientation `(roll, pitch, yaw)` in radians. |
 | `start_ang` | `float` | Initial camera gimbal angle in degrees. |
@@ -59,7 +60,23 @@ The canonical PKL file stores a list of Python dictionaries. Each sample contain
 | `gt_traj` | `float[N,3]` | Ground-truth trajectory points. |
 | `gt_traj_len` | `float` | Ground-truth trajectory length. |
 
-The Parquet table includes the same structured fields and additional convenience columns such as `sample_index`, `start_x`, `start_y`, `start_z`, `target_x`, `target_y`, `target_z`, and `gt_traj_num_points`. The `folder` field is omitted from the table because `sample_index` provides the browsing index. The Parquet file is provided for browsing and visualization in the Hugging Face Dataset Viewer.
+The Parquet table includes the same structured fields and additional convenience columns such as `sample_index`, `start_x`, `start_y`, `start_z`, `target_x`, `target_y`, `target_z`, and `gt_traj_num_points`. The Parquet file is provided for browsing and visualization in the Hugging Face Dataset Viewer.
+
+## Trajectory-Aligned Images
+
+Trajectory-aligned image archives are available under [`images/`](https://huggingface.co/datasets/EmbodiedCity/EmbodiedNav-Bench/tree/main/images).
+
+This release is about 56.7 GB and is distributed as five ZIP archives together with `merged_upload_images_zip_manifest.json`.
+
+After extraction, folders `0-5036` correspond directly to the `sample_index` field in `navi_data.pkl` and the viewer table.
+
+| Archive | Sample index range |
+| :-- | :-- |
+| `merged_upload_images_part01_0000-1007.zip` | `0-1007` |
+| `merged_upload_images_part02_1008-2015.zip` | `1008-2015` |
+| `merged_upload_images_part03_2016-3022.zip` | `2016-3022` |
+| `merged_upload_images_part04_3023-4029.zip` | `3023-4029` |
+| `merged_upload_images_part05_4030-5036.zip` | `4030-5036` |
 
 ## Usage