python 图像批量png转jpg格式

方法一： 适用win和linux

import os
import sys

from PIL import Image

input_folder=r'F:\VOC2012\PNGImages'  #源文件夹，包含.png格式图片
output_folder=r'F:\VOC2012\jpg_image'# 输出文件夹
#training_data=[]    
a=[]
for root, dirs, files in os.walk(input_folder):
    for filename in (x for x in files if x.endswith('.png')):
        filepath = os.path.join(root, filename) 
        
        object_class = filename.split('.')[0]
        a.append(object_class)
    print(a)
    
for i in a:
    old_path=input_folder+"\\"+str(i)+'.png'
    new_path=output_folder+"\\"+str(i)+'.jpg'
    img=Image.open(old_path)
    img.save(new_path)

方法二： 只适合win，这种编码linux不识别

import os
import string
dirName = "D:your path\\"         #最后要加双斜杠，不然会报错
li=os.listdir(dirName)
for filename in li:
    newname = filename
    newname = newname.split(".")
    if newname[-1]=="png":
        newname[-1]="jpg"
        newname = str.join(".",newname)  #这里要用str.join
        filename = dirName+filename
        newname = dirName+newname
        os.rename(filename,newname)
        print(newname,"updated successfully")