背景：
待压缩的图片大小有几十KB到近10M大小不等，且绝大部分图片为JPG格式。这些待压缩图片放在picture文件夹下以及picture文件夹下的子文件夹中
现需要将picture文件夹下这些图片压缩到500KB以内，且图片格式转换为PNG格式。本代码指定压缩大小为190kb。
Python图片批量压缩到指定大小并将JPG转为PNG格式代码如下：
#!/usr/bin/python# -*- coding: UTF-8 -*-"""@author:ZSW@file:picture_compress.py@time:/08/06"""import base64import ioimport osfrom PIL import Imagefrom PIL import ImageFileimport cv2# newpath = 'D:\picture_test\picture_test'# if not os.path.exists(newpath):#os.mkdir(newpath)# 压缩图片文件def compress_image(outfile, mb=190, 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 190kb: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) // 1024print(o_size, mb)if o_size <= mb:print(outfile)print(outfile.split('.')[0] + '.png')return outfileImageFile.LOAD_TRUNCATED_IMAGES = Truewhile o_size > mb:im = Image.open(outfile)x, y = im.sizeout = im.resize((int(x * k), int(y * k)), Image.ANTIALIAS)try:out.save(outfile, quality=quality)except Exception as e:print(e)breako_size = os.path.getsize(outfile) // 1024return outfile# 压缩base64的图片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()) // 1024if o_size <= mb:return b64im_out = imwhile o_size > mb:img = Image.open(im_out)x, y = img.sizeout = 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()) // 1024b64 = base64.b64encode(im_out.getvalue())im_out.close()return str(b64, encoding='utf8')#将指定文件夹filePath下的 文件地址 和 子文夹下的文件地址 塞进picuture_list列表中def read_file(filePath):picuture_list = []for dirpath, dirnames, filenames in os.walk(filePath):path = [os.path.join(dirpath, names) for names in filenames]picuture_list.extend(path)return picuture_list#jpg格式转为png格式def jpg_to_png(file):if file.endswith('JPG') or file.endswith('jpg'):# 要指明重命名之后的路径src = os.path.join(filePath, file)r_name = file.split('.')[0] + '.png'dct = os.path.join(filePath, r_name)os.rename(src, dct)if __name__ == '__main__':filePath = 'D:\picture' #图片位置outfile = read_file(filePath)for file in outfile:# compress_image(file) #先压缩图片jpg_to_png(file) #再将图片转为PNG格式
经压缩转换后图片未失真，很清晰！
参考：/weixin_38007235/article/details/105914956
/dl1456074580/article/details/106386883/
