class_docstr: Pads a Numpy image to the given size
  Return a Numpy image / image pair
  Arguments
  ---------
  :param size: (tuple or list):
      size of crop
code: def __init__(self, size):
      self.size = size
  
imports: import os
  import random
  import math
  import numpy
  import torch
label_desc: Use image node_id 1 to create a new PadNumpy object  with example: obj = PadNumpy(size)