为了保障网站的访问速度，应该对网站文章中使用的配图定义一些规范：

1. 格式使用 jpg 而不是 png
2. 限定最大宽度，如图片宽度小于 700px 时使用原图，否则限定宽度为700等比缩放
3. 同时生成 webp 格式的图片，在支持 webp 的浏览器中返回 webp 图片

老图片可以使用以下 Python 脚本进行处理

# coding:utf-8

import os
from PIL import Image
import cv2

def resize_image(infile, outfile='', x_s=700):
    """修改图片尺寸
    :param infile: 图片源文件
    :param outfile: 重设尺寸文件保存地址
    :param x_s: 设置的宽度
    :return:
    """
    im = Image.open(infile)
    x, y = im.size
    if x > x_s:
        y_s = int(y * x_s / x)
        out = im.resize((x_s, y_s), Image.ANTIALIAS)
    else:
        out = im

    out = out.convert('RGB')
    out.save(outfile, compress_level=9)

def compress(in_path, out_path, quality=100):
    print('\t', out_path)

    img = cv2.imread(in_path, cv2.IMREAD_UNCHANGED)
    if img is None:
        # raise Exception(f'read img failed: {in_path}')
        print(f'read img failed: {in_path}')
        return

    ext = os.path.splitext(out_path)[-1].strip('.')
    if ext == 'jpg':
        cv2.imwrite(out_path, img, [
            cv2.IMWRITE_JPEG_QUALITY, quality,
            cv2.IMWRITE_JPEG_PROGRESSIVE, 1,
            cv2.IMWRITE_JPEG_OPTIMIZE, 1,
        ])
    elif ext == 'png':
        cv2.imwrite(out_path, img, [
            cv2.IMWRITE_PNG_COMPRESSION, 9-int(quality/100*9)
        ])
    elif ext == 'webp':
        cv2.imwrite(out_path, img, [
            cv2.IMWRITE_WEBP_QUALITY, quality
        ])
    else:
        raise Exception(f'unknown file ext: {ext}')

def main():
    images_paths = [
        'old_images',
        'old_images/images',
    ]

    sqls = []
    for images_path in images_paths:
        for img_name in os.listdir(images_path):
            if img_name in ['.DS_Store', 'images']:
                continue

            name, ext = os.path.splitext(img_name)
            if len(ext) > 5:
                name = img_name
                ext = ''

            ext = ext.lower()

            if ext in ['.gif', '.jfif', '.zip', '.webp']:
                continue

            # 只处理以下三种格式
            if ext not in ['.png', '.jpeg', '.jpg']:
                print(f'ERROR: {img_name}')
                continue

            # 图片完整路径
            full_path = os.path.join(images_path, img_name)

            if not os.path.exists(f'temp/{images_path}'):
                os.makedirs(f'temp/{images_path}')
            if not os.path.exists(f'temp_webp/{images_path.replace("images", "webp")}'):
                os.makedirs(f'temp_webp/{images_path.replace("images", "webp")}')

            temp_path = f'temp/{images_path}/{name}.jpg'

            # 先压缩尺寸 并且保存为jpg
            resize_image(full_path, temp_path)

            # 生成webp
            webp_path = f'temp_webp/{images_path.replace("images", "webp")}/{name}.webp'
            compress(in_path=temp_path, out_path=webp_path, quality=80)

            if ext == '.png':
                # png 的图片转 jpg，后续还需要修改数据库的逻辑
                new_image_name = f"{name}.jpg"
                sql = f'UPDATE `articles` SET `thumb` = REPLACE(`thumb`, "{img_name}", "{new_image_name}"), `background` = REPLACE(`background`, "{img_name}", "{new_image_name}"), `contents` = REPLACE(`contents`, "{img_name}", "{new_image_name}"), `update_time`=`update_time`;'
                sqls.append(sql)

    with open('result.sql', mode='w', encoding='utf-8') as f:
        f.write("\n".join(sqls))

if __name__ == '__main__':
    main()