Python 压缩图片至指定大小

@https://www.cnblogs.com/jum-bolg/p/13796595.html

import base64
import io
import os
from PIL import Image
from PIL import ImageFile


# 压缩图片文件，改变尺寸
def compress_image(outfile, mb=600, quality=85, k=0.9):
    """不改变图片尺寸压缩到指定大小
    :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 = os.path.getsize(outfile) // 1024
    print(o_size, mb)
    if o_size <= mb:
        return outfile

    ImageFile.LOAD_TRUNCATED_IMAGES = True
    while o_size > mb:
        im = Image.open(outfile)
        x, y = im.size
        out = im.resize((int(x * k), int(y * k)), Image.ANTIALIAS)
        try:
            out.save(outfile, quality=quality)
        except Exception as e:
            print(e)
            break
        o_size = os.path.getsize(outfile) // 1024
    return outfile

# 压缩base64的图片，改变尺寸
def compress_image_bs4(b64, mb=190, k=0.9):
    """不改变图片尺寸压缩到指定大小
    :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
    """
    f = base64.b64decode(b64)
    with io.BytesIO(f) as im:
        o_size = len(im.getvalue()) // 1024
        if o_size <= mb:
            return b64
        im_out = im
        while o_size > mb:
            img = Image.open(im_out)
            x, y = img.size
            out = img.resize((int(x * k), int(y * k)), Image.ANTIALIAS)
            im_out.close()
            im_out = io.BytesIO()
            out.save(im_out, 'jpeg')
            o_size = len(im_out.getvalue()) // 1024
        b64 = base64.b64encode(im_out.getvalue())
        im_out.close()
        return str(b64, encoding='utf8')


if __name__ == "__main__":
    for img in os.listdir('./out_img'):
        compress_image(outfile='./out_img/' + str(img)[0:-4] + '.png')
    print('完')

压缩图片质量，不改变尺寸

def compress_im(im_path):
    """
    图像压缩到5m以内
    :param file_path:
    :return:
    """
    target_m = 5
    img = cv2.imread(im_path)
    new_im_path = os.path.splitext(im_path)[0]+'_compression.jpg'
    quality = 95
    while quality > 10:
        cv2.imwrite(new_im_path, img, [cv2.IMWRITE_JPEG_QUALITY, quality])
        file_size = os.stat(new_im_path).st_size / 1000 / 1000
        logger.info('compress img {} to {} M'.format(im_path, str(file_size)))
        if file_size <= target_m:
            break
        quality -= 10 if file_size >= 6.5 else 5   # 图像大小大于6.5M时以-10衰减，否则以5衰减
    file = open(new_im_path, 'rb')
    # os.system('rm {}'.format(new_im_path))
    return file, new_im_path