if(err){
            res.render('addproduct',{
                mesg: err
            });
        }
            new product({
                _id: new mongoose.Types.ObjectId(),
                 image:req.body.image,
                 name: req.body.name,
                 price:  req.body.price,
                 description: req.body.description,
                 category: req.body.category,
             }).save(function(err)
             {
                 if(err){
                     console.log(err);
                     res.render('addProduct')
                 }else{
                 res.redirect('/products');
             }
             })
        });
    })
    //all function for uploading images and checking file
//storage engine
const storage= multer.diskStorage({
    destination: './Public/images/',
    filename: function(req, file, cb){
        cb(null, file.fieldname + '-' + Date.now() + path.extname(file.originalname));
    }
});
//upload method
const upload = multer({
    storage: storage
}).single('image');

this is code for getting a file from ./public/image folder
<div class= "two row">
                <% products.forEach(product => { %>
                    <div class="column">

                            <img src="./Public/images/<%req.files[0].filename%>" class="cover-img">
                            <p><%= product.name %></p>
                            <h3>&dollar;<%= product.price %></h3>
                         <!---  <p><%= product.description %></p>-->
                    </div>
               <% }); %>