BatchResizer.py

# To run this script, PIL or Pillow should be installed
# Also jpeg and png decoders (libraries) should be installed with PIl or Pillow
# Part of this code is from: http://pythoncentral.io/resize-image-python-batch/

import os
# Next is a parser for GETting command line OPTions
import getopt
import sys
from PIL import Image

# Parse the arguments
opts, args = getopt.getopt(sys.argv[1:], 'd:w:h:')

# Set 'empty' default values to the needed variables, so we can check passed arguments
directory = ''
width = -1
height = -1
 
# If an argument was passed in, assign it to the correct variable
for opt, arg in opts:
   if opt == '-d':
     directory = arg
   elif opt == '-w':
     width = int(arg)
   elif opt == '-h':
     height = int(arg)
 
# Check passed arguments
if width == -1 or height == -1 or directory == '':
   print('Invalid command line arguments. -d [directory] ' \
     '-w [width in px] -h [height in px] are required')
     # example: python BatchResizer.py -d /Users/Name/Desktop/Photos -w 405 -h 405
   # If an argument is missing exit the application.
   exit()

# Iterate through every image given in the directory argument and resize it
for image in os.listdir(directory):
   # Next line is to solve a hidden file bug
   if image == ".DS_Store":
     pass
   else:
     print('Resizing image ' + image)
     # Open the file 
     img = Image.open(os.path.join(directory, image))
     # Check whether file is landscape or portrait
     original_width, original_height = img.size
     if original_width > original_height: 
       # For landscape images
       baseWidth = width
       # Calculate the height using the same aspect ratio
       widthPercent = (baseWidth / float(img.size[0]))
       ratioHeight = int((float(img.size[1]) * float(widthPercent)))
       # Resize it.
       img = img.resize((baseWidth, ratioHeight), Image.BILINEAR)
       # Save it back to disk.
       img.save(os.path.join(directory, 'thumb-' + image))
     elif original_width < original_height:
       # For portrait images      
       baseHeight = height
       # Calculate the height using the same aspect ratio
       heightPercent = (baseHeight / float(img.size[1]))
       ratioWidth = int((float(img.size[0]) * float(heightPercent)))
       # Resize it.
       img = img.resize((ratioWidth, baseHeight), Image.BILINEAR) 
       # Save it back to disk.
       img.save(os.path.join(directory, 'thumb-' + image))
     else: # image must be square already then
       # Resize it.
       img = img.resize((width, height), Image.BILINEAR)
       # Save it back to disk.
       img.save(os.path.join(directory, 'thumb-' + image))

print('Batch processing complete.')