Rails ActiveStorage picks random file when no file attached - ruby-on-rails

Question

Im kinda new with Rails and ActiveStorage, I've been creating a simple app where a user can create an image with a title and a description and attache a picture to it.
I used scaffold referenced to user to create the Image part, and here is the image model :
class Image < ApplicationRecord
belongs_to :user
has_one_attached :picture
end
and here is the form:
<%= form_with(model: image) do |form| %>
<% if image.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(image.errors.count, "error") %> prohibited this image from being saved:</h2>
<ul>
<% image.errors.each do |error| %>
<li><%= error.full_message %></li>
<% end %>
</ul>
</div>
<% end %>
<div class="field">
<%= form.label :title %>
<%= form.text_field :title %>
</div>
<div class="field">
<%= form.label :description %>
<%= form.text_field :description %>
</div>
<div class="field">
<%= form.label :picture %>
<%= form.file_field :picture, accept: 'image/png,image/jpeg,image/jpg' %>
</div>
<div class="actions">
<%= form.submit %>
</div>
<% end %>
<script type="text/javascript">
$('#image_picture').bind('change', function(){
var size_in_megabytes = this.files[0].size/1024/1024;
if(size_in_megabytes > 5){
alert("Maximum file size is 5Mo")
}
})
</script>
and the image_controller :
class ImagesController < ApplicationController
before_action :set_image, only: %i[ show edit update destroy ]
# GET /images or /images.json
def index
#images = Image.all
end
# GET /images/1 or /images/1.json
def show
end
# GET /images/new
def new
#image = Image.new
end
# GET /images/1/edit
def edit
end
# POST /images or /images.json
def create
#image = Image.new(image_params)
#image.user = current_user
respond_to do |format|
if #image.save
format.html { redirect_to #image, notice: "Image was successfully created." }
format.json { render :show, status: :created, location: #image }
else
format.html { render :new, status: :unprocessable_entity }
format.json { render json: #image.errors, status: :unprocessable_entity }
end
end
end
# PATCH/PUT /images/1 or /images/1.json
def update
respond_to do |format|
if #image.update(image_params)
format.html { redirect_to #image, notice: "Image was successfully updated." }
format.json { render :show, status: :ok, location: #image }
else
format.html { render :edit, status: :unprocessable_entity }
format.json { render json: #image.errors, status: :unprocessable_entity }
end
end
end
# DELETE /images/1 or /images/1.json
def destroy
#image.destroy
respond_to do |format|
format.html { redirect_to images_url, notice: "Image was successfully destroyed." }
format.json { head :no_content }
end
end
private
# Use callbacks to share common setup or constraints between actions.
def set_image
#image = Image.find(params[:id])
end
# Only allow a list of trusted parameters through.
def image_params
params.require(:image).permit(:title, :description, :user_id, :picture)
end
end
When I submit the form without an image, it choose a random image from my local repo and attache it to the record, I dnt know why and how to stop it