file still uploads with multer even after failed form validation

I have a form for adding a product which lets a user input product name, description etc. and also allows an image upload.

In my app.js file which is my entry point, I have:

const fileStorage = multer.diskStorage({
    destination: (req, file, cb) => {
      cb(null, 'uploads');
    },
    filename: (req, file, cb) => {
       cb(null, new Date().toISOString() + '-' + file.originalname);
    }
  });


  const fileFilter = (req, file, cb) => {
    if (
      file.mimetype === 'image/png' ||
      file.mimetype === 'image/jpg' ||
      file.mimetype === 'image/jpeg'
    ) {
      cb(null, true);
    } else {
      cb(null, false);
    }
  };

app.use(multer({ storage: fileStorage , fileFilter: fileFilter, limits: { fileSize: 100000} }).single('image'));

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Here is my controller:

exports.postAddListing = (req, res, next) => {
    const title = req.body.title;
    const category = req.body.category;
    const description = req.body.description;
    const errors = validationResult(req);
    if (!errors.isEmpty()) {
        return res.status(422).render('account/add-listing', {
            pageTitle: 'Add Item',
            path: '/account/add-listing',
            errorMessage: errors.array(),
            successMessage: null,
            oldInput: {
                title: title,
                description: description
            }
        });
    }

    const image = req.file;
    const imageUrl = image.path;

    const product = new Product({
        title: title,
        category: category,
        description: description,
        userId: req.user,
        datePosted: Date.now(),
        imageUrl: imageUrl
    });
    product.save()
    .then(result => {
        const successMessage = req.flash('success', 'Item sucessfully added');
        res.redirect('/account/add-listing');
    })
    .catch(err => console.log(err));
};

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I am using express-validator for form validation. The problem I have is that if I for example leave all fields empty but choose an image, validation will fire and I will get error messages but the image will still upload. If form validation fails I don't want the image to upload but not sure how to achieve that.