Allow users to upload image and modify then within app using opencv

My app should allow user to upload an image from browser, followed by some operations using opencv, and then it needs to display modified image back. My problem is in update_output function. When I pass i, I see the image in the browser, however if I pass dataURI (modified version of image using opencv), then image is never displayed in a browser. Could someone help me please?

  #app = Dash(__name__, external_stylesheets=external_stylesheets)
  app.layout = html.Div([
              'Drag and Drop or ',
              html.A('Select Files')
      dcc.Store(id='store-data', storage_type='memory')
  @app.callback(Output('store-data', 'data'), Input('upload-image', 'contents') )
  def store_data(value): return value
  def data_uri_to_cv2_img(uri):
      encoded_data = uri.split(',')[1]
      nparr = np.fromstring(base64.b64decode(encoded_data), np.uint8)
      img = cv2.imdecode(nparr, cv2.IMREAD_COLOR)
      return img
  def parse_contents(contents):
      return html.Div([
          html.Img(src=contents, style={'height':'10%', 'width':'10%'})
      Output('output-image-upload', 'children'),
      Input('store-data', 'data')
  def update_output(images):
      if not images:
      children = []
      for i in images:
        img1 = data_uri_to_cv2_img(i)
        #some operations -- skip for now
        _, buffer = cv2.imencode('.jpg', img1)
        jpg_as_text = base64.b64encode(buffer.tobytes())
        dataURI = 'data:image/jpeg;base64,' + str(jpg_as_text) 
      return children
  if __name__ == '__main__':
     app.run_server(host='localhost',port=8005, debug = True)