Image upload with vueJS and Laravel

I want to add a input file for a vueJS component including a form. Here is my component :

        <form @submit.prevent="sendForm" enctype="multipart/form-data">
            <div class="col-md-6">
                <div class="form-group">
                    <label for="title">Nom de l'évènement</label>
                    <input id="title" name="title" type="text" class="form-control" v-bind:class="{ 'is-invalid': errors.title }" v-model="fields.title">
                    <div v-if="errors && errors.title" class="text-danger py-2">{{ errors.title[0] }}</div>
                </div>
            </div>

            <div class="col-md-6">
                <label for="image">Image ou flyer de l'évènement</label>
                <div class="custom-file">
                    <input type="file" class="custom-file-input" id="image" name="image" @change="imageChange" accept=".png, .jpg, .jpeg" v-bind:class="{ 'is-invalid': errors.image }">
                    <label class="custom-file-label" for="image">{{ imageLabel }}</label>
                    <div v-if="errors && errors.image" class="text-danger py-2">{{ errors.image[0] }}</div>
                </div>
            </div>
    </form>

<script>

import {LMap, LTileLayer} from 'vue2-leaflet';

export default {
    components: {
        LMap,
        LTileLayer,
    },
    data () {
        return {
            // Some data are not usefull for this question
            url: 'https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png',
            zoom: 5,
            center: [47, 2.5],
            bounds: null,
            markerLatLng: null,
            city: null,
            error: null,
            errors: {},
            fields: {},
            mapLoading: false,
            typingTimer: 1000,
            imageLabel: 'Sélectionner un fichier'
        };
    },
    methods: {
        sendForm() {
            axios.post('/events', this.fields)
                .then(response => {
                    this.field = {}
                    console.log(response)
                })
                .catch(err => {
                    if (err.response.status === 422) {
                        this.errors = err.response.data.errors || { }
                    }
                });
        },
        imageChange(event) {
            this.imageLabel = event.target.files[0].name,
            this.fields.image = event.target.files[0];
        }
    }
}

Here is my controller :

    public function store(Request $request)
{
    // var_dump($request->image());

    $this->validate($request, [
        'title' => 'required|string|unique:events',
        'description' => 'required',
        'start_date' => 'required|date',
        'end_date' => 'date',
        'latitude' => 'required|numeric',
        'longitude' => 'required|numeric',
        'image' => 'required|image'
    ]);


    // $imageName = Str::slug($request->get('title'), '-') . '.' .$request->image->getClientOriginalExtension();
    // $request->image->move(public_path('images/events'), $imageName);

    return response()->json(null, 200);
}

When i fill and submit my form i got the following message : The image field is required.

It's just like the image is didn't send, someone have an idea please ? I tryied to follow this tutorial for the image upload : https://www.itsolutionstuff.com/post/laravel-vue-js-image-upload-example-with-demoexample.html.

Thank's a lot for everyone who read this entierely and will try to help me.

Florent