基于 Pillow 的图片压缩

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


# 获取图片文件大小(KB)
def get_size(file):
    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


# 压缩图片到指定大小
def compress_image(infile, outfile='', mb=500, step=10, quality=80):
    """
    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
    """
    if os.path.exists(outfile):
        return
    o_size = get_size(infile)
    if o_size <= mb:
        return infile
    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)


# 批量压缩示例
if __name__ == '__main__':
    input_dir = r"输入目录"
    output_dir = r"输出目录"

    # 使用线程池提高速度
    pool = ThreadPool(4)
    for i in os.listdir(input_dir):
        infile = os.path.join(input_dir, i)
        outfile = os.path.join(output_dir, i)
        pool.apply_async(compress_image, args=(infile, outfile))
    pool.close()
    pool.join()