...
  FImageH.LoadFromResourceName(HInstance, 'IMAGEH');
  ...

  FInputImage.Canvas.Lock;
  try
    FInputImage.Canvas.CopyMode := cmSrcCopy;
    FInputImage.Canvas.Brush.Color := clRed;
    FInputImage.Canvas.Rectangle(SR);
    FInputImage.Canvas.StretchDraw(SR, FImageV);
  finally
    FInputImage.Canvas.Unlock;
  end;