emoji_creator.py

import sys
from PIL import Image

def main():
    filename = ""
    if len(sys.argv) <= 1:
        print("input filename:")
        filename = input()
    else:
        filename = sys.argv[1]
    img = Image.open(filename)
    size = img.size
    greater_side = size[0] if size[0] > size[1] else size[1]
    ratio = 128.0 / float(greater_side)
    img = img.resize((int(size[0] * ratio), int(size[1] * ratio)))
    fname = filename.split(".")
    img.save("%s_resized.%s" % (".".join(fname[0:-1]), fname[-1]))

if __name__ == '__main__':
    main()