Je souhaite que l'image stockée soit supprimée lors de la mise à jour avec une nouvelle image

Je suis nouveau dans codeigniter et j'ai des problèmes lors de la modification de l'image de l'élément, non pas qu'il ne soit pas mis à jour, mais il y a trop d'images dans le répertoire du dossier de téléchargement.

Je veux faire Je souhaite que l'image précédemment stockée soit supprimée du répertoire de téléchargement lorsque je mets à jour une nouvelle image.

Voici mon contrôleur:

function shopUpdate($shop_id, $shopInfo) {
        $this->db->where('shop_id', $shop_id);
        if($shopInfo) {
            $query = $this->db->update('shop', $shopInfo);
            if ($query) {
                return true;
            } else {
                return false;
            }
        } else {
            return false;
        }
    }

Voici mon modèle:

function edit($shop_id = null){

        if ( ! $this->ion_auth->logged_in() OR ! $this->ion_auth->is_admin())
        {
            redirect('auth', 'refresh');
        }
        /* Breadcrumbs */
        $this->data['breadcrumb'] = $this->breadcrumbs->show();

        /* Variables */
        $tables = $this->config->item('tables', 'ion_auth');

        $this->data['shop_id']   = $shop_id;
        /* Get all category */          
        $this->data['shopInfo'] = $this->shop_model->getShopInfo($shop_id);
        //echo "<pre>";print_r( $this->data['shopInfo']);echo "</pre>";exit;

        /* Validate form input */
        $this->form_validation->set_rules('shop_name', 'Shop Name', 'trim|required'); 
        $this->form_validation->set_rules('shop_latidude', 'Shop Latidude', 'trim|required'); 
        $this->form_validation->set_rules('shop_longitude', 'Shop Longitude', 'trim|required');   



        if($this->form_validation->run() == true) {
            $config['upload_path'] =  './assets/uploads/shop/';
            //die(var_dump(is_dir($config['upload_path'])));
            $config['allowed_types'] = 'gif|jpg|png';
            $config['max_size']    = '1024';
            $config['overwrite'] = TRUE;

            $this->load->library('upload', $config);
            $this->upload->initialize($config);
            $img = "logo";

            $img_upload = $this->upload->do_upload($img);
            $data  = $this->upload->data();
            $file  = array('file_name' => $data['file_name'] );           
            $data  = array('upload_data' => $this->upload->data());
            $photo = base_url().'assets/uploads/shop/'.$file['file_name'];

            if($img_upload == 1 ) $post_photo = $photo;
            else $post_photo = $this->input->post('hidden_photo');

            if($this->input->post('status')){
                $status = 1;
            }else{
                $status = 0;
            }
            $shopInfo = array(
                    'shop_name'     =>  $this->input->post('shop_name'),
                    'merchant_id'   =>  $this->input->post('merchant_id'),
                    'photo'         =>  $post_photo,
                    'description'   =>  $this->input->post('shop_desc'),
                    'registered_date'=> date('Y-m-d H:i:s'),
                    'is_active'     =>  1,
                    'shop_location' =>  $this->input->post('shop_loc'),
                    'shop_address'  =>  $this->input->post('shop_add'),
                    'shop_phone'    =>  $this->input->post('shop_ph'),
                    'shop_latitude' =>  $this->input->post('shop_latidude'),
                    'shop_longitude'=>  $this->input->post('shop_longitude'),
                    'open_hour' => $this->input->post('open_hour'),
                    'close_hour' => $this->input->post('close_hour'),
                    'remark' => $this->input->post('remark'),
                    'approved' => $status
                );

            $this->shop_model->shopUpdate($shop_id, $shopInfo);

            redirect(base_url() . 'admin/shop', 'refresh');

        } else {

            $this->data['message'] = (validation_errors() ? validation_errors() : ($this->ion_auth->errors() ? $this->ion_auth->errors() : $this->session->flashdata('message')));
            /* Load Template */
            $this->data['merchant'] = $this->merchant_model->getAllMerchants();
            $this->template->admin_render("admin/shop/edit", $this->data);
        }

    }