python实现图片压缩处理

一、前言

今天在做人脸检测的时候遇到了图片过大的问题，解决方法是在提交图片前先将图片进行压缩。

二、实现代码

from PIL import Image
import os


def get_size(file):
    # 获取文件大小:KB
    size = os.path.getsize(file)
    return size / 1024


def get_outfile(infile, outfile):
    if outfile:
        return outfile
    dir, suffix = os.path.splitext(infile)
    outfile = '{}-out{}'.format(dir, suffix)
    return outfile


def compress_image(infile, outfile='', mb=1024, step=10, quality=80):
    """不改变图片尺寸压缩到指定大小
    :param infile: 压缩源文件
    :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 = get_size(infile)
    if o_size <= mb:
        return infile
    outfile = get_outfile(infile, outfile)
    while o_size > mb:
        im = Image.open(infile)
        im.save(outfile, quality=quality)
        if quality - step < 0:
            break
        quality -= step
        o_size = get_size(outfile)
    return outfile, get_size(outfile)


def resize_image(infile, outfile='', x_s=1376):
    """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
    y_s = int(y * x_s / x)
    out = im.resize((x_s, y_s), Image.ANTIALIAS)
    outfile = get_outfile(infile, outfile)
    out.save(outfile)


if __name__ == '__main__':
    resize_image("static/jpgtest/test/4.jpg", "static/jpgtest/test/4.jpg")
    compress_image("static/jpgtest/test/4.jpg", "static/jpgtest/test/4.jpg")

三、注意事项

图片分辨率较大时可以先处理图片分辨率再压缩