hd-to-sd.py

import os
import re

files = []
for (root, dirnames, filenames) in os.walk('.'):
    if len(filenames) != 0:
        for one in filenames:
            files.append(os.path.join(root, one))

isPng = re.compile(r'.*\.png$')
isHdPng = re.compile(r'.*-hd\.png$')

pngFiles = []
for f in files:
    if isPng.match(f):
        pngFiles.append(f)

hdPngFiles = []
for f in files:
    if isHdPng.match(f):
        hdPngFiles.append(f)

sdPngFiles = []
for f in pngFiles:
    if f not in hdPngFiles:
        sdPngFiles.append(f)

# check whether these two lists cover the same files
excludeFiles = []
for f in sdPngFiles:
    correspondingFile = re.sub(r'\.png$', r'-hd.png', f)
    if correspondingFile not in hdPngFiles:
        print f + ' doesn\'t have a corresponding hd file ' + correspondingFile
        excludeFiles.append(f)

for f in hdPngFiles:
    correspondingFile = re.sub(r'-hd\.png$', r'.png', f)
    if correspondingFile not in sdPngFiles:
        print f + ' doesn\'t have a corresponding normal file ' + correspondingFile
        excludeFiles.append(f)

print
print 'Excluded Files:'
for f in excludeFiles:
    if f in sdPngFiles:
        sdPngFiles.remove(f)
    if f in hdPngFiles:
        hdPngFiles.remove(f)
    print '  ' + f

# replace!
for f in hdPngFiles:
    correspondingFile = re.sub(r'-hd\.png$', r'.png', f)
    os.rename(f, correspondingFile)

print 'Done!'