Confirm patch datatype before autoscaling

extensions/chaeo/products.py

@@ -179,7 +179,11 @@ def export_patches_from_zstack(
 
         ext = 'tif' if make_3d else 'png'
         fname = f'{prefix}-la{obj.label:04d}-zi{obj.zi:04d}.{ext}'
-        _write_patch_to_file(where, fname, resample_to_8bit(patch))
+
+        if patch.dtype is np.dtype('uint16'):
+            _write_patch_to_file(where, fname, resample_to_8bit(patch))
+        else:
+            _write_patch_to_file(where, fname, patch)
 
         exported.append({
             'df_index': idx,