title: AttributeError: 'numpy.ndarray' object has no attribute 'save'
body: <p>i have short code for crop image all image in folder that i labeled and save as csv using opencv like this:</p>
  
  <pre><code>import os, sys
  from PIL import Image
  import cv2
  import pandas as pd
  
  # The annotation file consists of image names, text label, 
  # bounding box information like xmin, ymin, xmax and ymax.
  ANNOTATION_FILE = 'data/annot_crop_plate.csv'
  df = pd.read_csv(ANNOTATION_FILE)
  
  #image directory path
  IMG_DIR = 'data/images'
  # The cropped images will be stored here
  CROP_DIR = 'data/crops'
  
  files = df['filename']
  
  size = (200,200)
  
  for file in files:
      print(file)
      img = cv2.imread(IMG_DIR +'/' + file)
      annot_data = df[df['filename'] == file]
      xmin = int(annot_data['xmin'])
      ymin = int(annot_data['ymin'])
      xmax = int(annot_data['xmax'])
      ymax = int(annot_data['ymax'])
      crop = img[ymin:ymax,xmin:xmax]
      new_crop = cv2.resize(crop, dsize=size, interpolation=cv2.INTER_CUBIC)
      new_crop.save(CROP_DIR + '/' + file.split('.')[0] + '.png', 'PNG', quality=90)
  </code></pre>
  
  <p>but in the end of line have said "AttributeError: 'numpy.ndarray' object has no attribute 'save'"</p>