diff --git a/tools/data_converter/kitti_data_utils.py b/tools/data_converter/kitti_data_utils.py
index cae84cc6ea..40e8b81596 100644
--- a/tools/data_converter/kitti_data_utils.py
+++ b/tools/data_converter/kitti_data_utils.py
@@ -46,8 +46,9 @@ def get_image_path(idx,
                    relative_path=True,
                    exist_check=True,
                    info_type='image_2',
+                   file_tail='.png',
                    use_prefix_id=False):
-    return get_kitti_info_path(idx, prefix, info_type, '.png', training,
+    return get_kitti_info_path(idx, prefix, info_type, file_tail, training,
                                relative_path, exist_check, use_prefix_id)
 
 
@@ -378,6 +379,7 @@ def gather_single(self, idx):
             self.training,
             self.relative_path,
             info_type='image_0',
+            file_tail='.jpg',
             use_prefix_id=True)
         if self.with_imageshape:
             img_path = image_info['image_path']
diff --git a/tools/data_converter/waymo_converter.py b/tools/data_converter/waymo_converter.py
index f991514bd0..dae5dec236 100644
--- a/tools/data_converter/waymo_converter.py
+++ b/tools/data_converter/waymo_converter.py
@@ -130,7 +130,9 @@ def __len__(self):
         return len(self.tfrecord_pathnames)
 
     def save_image(self, frame, file_idx, frame_idx):
-        """Parse and save the images in png format.
+        """Parse and save the images in jpg format. Jpg is the original format
+        used by Waymo Open dataset. Saving in png format will cause huge (~3x)
+        unnesssary storage waste.
 
         Args:
             frame (:obj:`Frame`): Open dataset frame proto.
@@ -140,9 +142,9 @@ def save_image(self, frame, file_idx, frame_idx):
         for img in frame.images:
             img_path = f'{self.image_save_dir}{str(img.name - 1)}/' + \
                 f'{self.prefix}{str(file_idx).zfill(3)}' + \
-                f'{str(frame_idx).zfill(3)}.png'
-            img = mmcv.imfrombytes(img.image)
-            mmcv.imwrite(img, img_path)
+                f'{str(frame_idx).zfill(3)}.jpg'
+            with open(img_path, 'wb') as fp:
+                fp.write(img.image)
 
     def save_calib(self, frame, file_idx, frame_idx):
         """Parse and save the calibration data.