diff --git a/api/onnx_web/chain/result.py b/api/onnx_web/chain/result.py
index 813f5863..ce1ee515 100644
--- a/api/onnx_web/chain/result.py
+++ b/api/onnx_web/chain/result.py
@@ -3,6 +3,41 @@ from typing import List, Optional
 import numpy as np
 from PIL import Image
 
+from ..output import json_params
+from ..params import Border, HighresParams, ImageParams, Size, UpscaleParams
+
+
+class ImageMetadata:
+    border: Border
+    highres: HighresParams
+    params: ImageParams
+    size: Size
+    upscale: UpscaleParams
+
+    def __init__(
+        self,
+        params: ImageParams,
+        size: Size,
+        upscale: Optional[UpscaleParams] = None,
+        border: Optional[Border] = None,
+        highres: Optional[HighresParams] = None,
+    ) -> None:
+        self.params = params
+        self.size = size
+        self.upscale = upscale
+        self.border = border
+        self.highres = highres
+
+    def tojson(self):
+        return json_params(
+            [],
+            self.params,
+            self.size,
+            upscale=self.upscale,
+            border=self.border,
+            highres=self.highres,
+        )
+
 
 class StageResult:
     """
@@ -14,6 +49,7 @@ class StageResult:
 
     arrays: Optional[List[np.ndarray]]
     images: Optional[List[Image.Image]]
+    metadata: List[ImageMetadata]
 
     @staticmethod
     def empty():
@@ -60,6 +96,32 @@ class StageResult:
         else:
             return []
 
+    def push_array(self, array: np.ndarray, metadata: Optional[ImageMetadata]):
+        if self.arrays is not None:
+            self.arrays.append(array)
+        elif self.images is not None:
+            self.images.append(Image.fromarray(np.uint8(array), shape_mode(array)))
+        else:
+            raise ValueError("invalid stage result")
+
+        if metadata is not None:
+            self.metadata.append(metadata)
+        else:
+            self.metadata.append(ImageMetadata())
+
+    def push_image(self, image: Image.Image, metadata: Optional[ImageMetadata]):
+        if self.images is not None:
+            self.images.append(image)
+        elif self.arrays is not None:
+            self.arrays.append(np.array(image))
+        else:
+            raise ValueError("invalid stage result")
+
+        if metadata is not None:
+            self.metadata.append(metadata)
+        else:
+            self.metadata.append(ImageMetadata())
+
 
 def shape_mode(arr: np.ndarray) -> str:
     if len(arr.shape) != 3: