图片大小压缩

from PIL import Image
import os
from multiprocessing.pool import ThreadPool

# 获取图片文件大小
def get_size(file):
    # 获取文件大小:KB
    size = os.path.getsize(file)
    return size / 1024


# 拼接输出文件地址
def get_outfile(infile, outfile):
    if outfile:
        return outfile
    dir, suffix = os.path.splitext(infile)
    outfile = '{}-out{}'.format(dir, suffix)
    return outfile


# 压缩文件到指定大小
def compress_image(infile, outfile='', mb=500, step=10, quality=80):
    # 判断该张图片是否压缩
    if os.path.exists(outfile):
        return
    """不改变图片尺寸压缩到指定大小
    :param infile: 压缩源文件
    :param outfile: 压缩文件保存地址
    :param mb: 压缩目标，KB
    :param step: 每次调整的压缩比率
    :param quality: 初始压缩比率
    :return: 压缩文件地址，压缩文件大小
    """
    o_size = get_size(infile)
    if o_size <= mb:
        shutil.copyfile(infile,outfile)
        return f"cp:{infile}>{outfile}"
    outfile = get_outfile(infile, outfile)
    while o_size > mb:
        im = Image.open(infile)
        im.save(outfile, quality=quality)
        if quality - step < 0:
            break
        quality -= step
        o_size = get_size(outfile)
    return outfile, get_size(outfile)


# 默认600k，但是可能不会到600K,有的压缩不到
path_a = r"文件路径"
path_b = r"文件路径"
# 使用线程池提高速度
s = ThreadPool(12)
for i in os.listdir(path_a):
    infile = os.path.join(path_a, i)
    outfile = os.path.join(path_b, i)
    # if os.path.exists(outfile):
    #     continue
    print(infile)
    s.apply_async(compress_image, args=(infile, outfile))
    # compress_image(infile,outfile)
s.close()
s.join()