diff --git a/src/transformers/models/owlv2/image_processing_owlv2.py b/src/transformers/models/owlv2/image_processing_owlv2.py
index dd32dc9f141183..3dcf145ea41ffc 100644
--- a/src/transformers/models/owlv2/image_processing_owlv2.py
+++ b/src/transformers/models/owlv2/image_processing_owlv2.py
@@ -19,7 +19,7 @@
 
 import numpy as np
 
-from ...image_processing_utils import BaseImageProcessor, BatchFeature
+from ...image_processing_utils import BaseImageProcessor, BatchFeature, get_size_dict
 from ...image_transforms import (
     center_to_corners_format,
     pad,
@@ -399,6 +399,7 @@ def preprocess(
         image_std = image_std if image_std is not None else self.image_std
 
         size = size if size is not None else self.size
+        size = get_size_dict(size)  # for BC
 
         images = make_list_of_images(images)