need help in compassing an image in the backend

hello i am all new to node i build the backend using the express framework , i try to compress image on the fly , i use the formidable to receive the files, and for the compress i use compress-images,for storage i use mongodb , this is what i try to do, to compress in the same folder and replacing the original upload to the new compressed , cant figure how to do it tried to do like in the example code does not work , still pass the original file, some one help please

exports.createPost = (req, res) =>{
let form = new formidable.IncomingForm();
form.keepExtensions = true;
form.maxFieldsSize= 2 * 1024 * 1024;
form.parse(req, (err, fields, files)=>{
    if(err){
        return res.status(400).json({error:'image could not be uploaded'});
    }
    let post = new Post(fields);
    const {emotion , color} = post;
    post = _.extend(post,ECBrige2(emotion,color));
    post.postedBy = req.profile;
    req.profile.hashed_password = undefined;
    req.profile.salt = undefined;
    if(files.photo){
        compress_images(files.photo.path,files.photo.path, {compress_force: true, statistic: false, autoupdate: true}, false,
                                            {jpg: {engine: 'jpegRecompress', command: ['--quality', 'high', '--min', '60','-m', 'smallfry']}},
                                            {png: {engine: 'pngquant', command: ['--quality=20-50', '--ext=-min.png', '--force']}},
                                            {svg: {engine: 'svgo', command: '--multipass'}},
                                            {gif: {engine: 'gifsicle', command: ['--colors', '64', '--use-col=web']}}, function(err, completed, statistic){
    if(err === null){
        fs.unlink(statistic.input, (err) => {
            if (err) throw err;
            console.log('successfully compressed and deleted '+statistic.input);
        });
        console.log('completed');
    }
});
    post.photo.data = fs.readFileSync(files.photo.path);
    post.photo.contentType = files.photo.type;    
    }
    
    post.save((err,result)=>{
        if(err){
            return res.status(400).json({error:err});
        }
        res.json(result);
    });
});

};