前言

常见的图像任务通常需要把照片统一成相同的格式，所以此文章正是为了统一格式而生，常见的主要有cv2和PIL.Image的相关操作，照片格式是一串数字加上后缀名

工具一：cv2

pip install opencv-python

之后就可以

import cv2

1.1 导包

import os
import cv2
import sys
import numpy as np

1.2 路径设置

path = r"C:\\Users\\86775\\test_change\\"
path2 = r"C:\\Users\\86775\\test_change2\\"

1.3 改格式重新传

1.3.1 用os.path.splitext()来判断

images = os.listdir(path)
for i in os.listdir(path):
    print(os.path.splitext(i))  # ('34474006827920603', '.png')
    if os.path.splitext(i)[1] == ".jpeg":
        img = cv2.imread(path + i)
        # print(img)
        new_imagename = i.replace(".jpeg", ".jpg")
        cv2.imwrite(path2 + new_imagename, img)
 
    elif os.path.splitext(i)[1] == ".png":
        img = cv2.imread(path + i)
        # print(img)
        new_imagename = i.replace(".png", ".jpg")
        cv2.imwrite(path2 + new_imagename, img)
 
    elif os.path.splitext(i)[1] == ".JPG":
        img = cv2.imread(path + i)
        # print(img)
        new_imagename = i.replace(".JPG", ".jpg")
        cv2.imwrite(path2 + new_imagename, img)
 
    elif os.path.splitext(i)[1] == ".PNG":
        img = cv2.imread(path + i)
        # print(img)
        new_imagename = i.replace(".PNG", ".jpg")
        cv2.imwrite(path2 + new_imagename, img)
 
    elif os.path.splitext(i)[1] == ".jpg":
        img = cv2.imread(path + i)
        # print(img)
        cv2.imwrite(path2 + i, img)

1.3.2 用split()来判断

images = os.listdir(path)
for i in os.listdir(path):
    print(i.split("."))
    if i.split(".")[1] == "jpeg":
        img = cv2.imread(path + i)
        # print(img)
        new_imagename = i.replace(".jpeg", ".jpg")
        cv2.imwrite(path2 + new_imagename, img)
 
    elif i.split(".")[1] == "png":
        img = cv2.imread(path + i)
        # print(img)
        new_imagename = i.replace(".png", ".jpg")
        cv2.imwrite(path2 + new_imagename, img)
 
    elif i.split(".")[1] == "JPG":
        img = cv2.imread(path + i)
        # print(img)
        new_imagename = i.replace(".JPG", ".jpg")
        cv2.imwrite(path2 + new_imagename, img)
 
    elif i.split(".")[1] == "PNG":
        img = cv2.imread(path + i)
        # print(img)
        new_imagename = i.replace(".PNG", ".jpg")
        cv2.imwrite(path2 + new_imagename, img)
 
    elif i.split(".")[1] == "jpg":
        img = cv2.imread(path + i)
        # print(img)
        cv2.imwrite(path2 + i, img)

1.4 查看结果

工具二：pillow

pip install pillow

之后就可以

from PIL import Image

2.1 导包

import os
from PIL import Image

2.2 路径设置

path = r"C:\\Users\\86775\\test_change\\"
path2 = r"C:\\Users\\86775\\test_change2\\"

2.3 写格式修改函数

RGBA意思是红色，绿色，蓝色，Alpha的色彩空间，Alpha指透明度，而JPG不支持透明度。
所以其他格式不转jpg可以直接保存为.png格式，转jpg就需要丢弃Alpha
img = img.convert(“RGB”)，转换成RGB，保证和jpg格式的通道数相同，也算一种图片类型变换的防报错机制

def jpeg2jpg(path_in, path_out):
    img = Image.open(path_in)
    img = img.convert("RGB")
    img.save(path_out, "JPEG", quality=80, optimize=True, progressive=True)
 
 
def png2jpg(path_in, path_out):
    img = Image.open(path_in)
    img = img.convert("RGB")
    img.save(path_out, "JPEG", quality=80, optimize=True, progressive=True)
 
 
def JPG2jpg(path_in, path_out):
    img = Image.open(path_in)
    img = img.convert("RGB")
    img.save(path_out, "JPEG", quality=80, optimize=True, progressive=True)
 
 
def PNG2jpg(path_in, path_out):
    img = Image.open(path_in)
    img = img.convert("RGB")
    img.save(path_out, "JPEG", quality=80, optimize=True, progressive=True)
 
 
def jpg2jpg(path_in, path_out):
    img = Image.open(path_in)
    img = img.convert("RGB")
    img.save(path_out, "JPEG", quality=80, optimize=True, progressive=True)

2.4 开始转换

images = os.listdir(path1)
for i in images:
    print(i)
    if os.path.splitext(i)[1] == ".jpeg":
        source = path1 + "\\" + str(i.split(".")[0]) + ".jpeg"
        target = path2 + "\\" + str(i.split(".")[0]) + ".jpg"
        jpeg2jpg(source, target)
    elif os.path.splitext(i)[1] == ".png":
        source = path1 + "\\" + str(i.split(".")[0]) + ".png"
        target = path2 + "\\" + str(i.split(".")[0]) + ".jpg"
        png2jpg(source, target)
    elif os.path.splitext(i)[1] == ".JPG":
        source = path1 + "\\" + str(i.split(".")[0]) + ".JPG"
        target = path2 + "\\" + str(i.split(".")[0]) + ".jpg"
        JPG2jpg(source, target)
    elif os.path.splitext(i)[1] == ".PNG":
        source = path1 + "\\" + str(i.split(".")[0]) + ".PNG"
        target = path2 + "\\" + str(i.split(".")[0]) + ".jpg"
        PNG2jpg(source, target)
    elif os.path.splitext(i)[1] == ".jpg":
        source = path1 + "\\" + str(i.split(".")[0]) + ".jpg"
        target = path2 + "\\" + str(i.split(".")[0]) + ".jpg"
        jpg2jpg(source, target)

2.5 查看结果