uploadCI.php

<?php defined('BASEPATH') OR exit('No direct script access allowed');
if( ! ini_get('date.timezone') )
{
   date_default_timezone_set('GMT');
}
header('Access-Control-Allow-Origin: *');
class Dashboard extends CI_Controller{
        public function __construct(){
                parent::__construct();
                $this->load->helper('form');
                $this->load->model('upload_model');
                if(!$this->session->userdata('logado')){
                    redirect("administration/login");
                }
        }

        public function index(){
                $data['albuns'] = $this->upload_model->consultarTodosAlbuns();
                $data['fotos'] = $this->db->get('tb_galeria')->result();
                $data['admin'] = $this->db->get('tb_usuarios')->result();
                $this->load->view('administration/dashboard', $data);
        }

        function mudarStatus(){
                $id = $this->input->post('id');
                $status = $this->input->post('status');
                $this->db->where('id', $id);
                if($status == "A"){
                    $this->db->set('status', "D");
                    $this->db->update('tb_galeria');
                }else{
                    $this->db->set('status', "A");
                    $this->db->update('tb_galeria');
                }
                redirect(base_url('dashboard'));
        }

        function upload(){
                $idAlbum = $this->input->post('album');
                $nome = $this->db->get_where('tb_albuns', array('id' => $idAlbum));
                $nome = $nome->row()->album_nome;
                $path = FCPATH . '/assets/admin/galeria/'.$nome;
                $nFiles = count($_FILES['arquivo']['tmp_name']);
                $files = $_FILES['arquivo'];
                $errors = array();
                for($i = 0; $i < $nFiles; $i++){
                    if($_FILES['arquivo']['error'][$i] != 0){
                        $errors[$i][] = 'Não foi possível fazer o upload do arquivo '.$_FILES['arquivo']['name'][$i];
                    }
                }
                if(sizeof($errors) == 0){
                    $this->load->library('upload');
                    $config['upload_path'] = $path.'/';
                    $config['allowed_types'] = 'jpg|jpeg|gif|png';
                    for ($i=0; $i <  $nFiles; $i++) {
                        $_FILES['arquivo']['name'] = $files['name'][$i];
                        $_FILES['arquivo']['type'] = $files['type'][$i];
                        $_FILES['arquivo']['tmp_name'] = $files['tmp_name'][$i];
                        $_FILES['arquivo']['error'] = $files['error'][$i];
                        $_FILES['arquivo']['size'] = $files['size'][$i];
                        //now we initialize the upload library
                        $this->upload->initialize($config);
                        if ($this->upload->do_upload('arquivo')) {
                            $data['uploads'][$i] = $this->upload->data();
                            $fotos  = array('path' => $data['uploads'][$i]['file_path'], 'ft_nome' => $data['uploads'][$i]['file_name'], 'status' => "A", 'idAlbum' => $idAlbum );
                            $this->upload_model->inserirImagens($fotos);
                        } else {
                            $data['upload_errors'][$i] = $this->upload->display_errors();
                        }
                    }
                            redirect(base_url('dashboard'));
                } else {
                    redirect(base_url('administration/dashboard', $errors));
                }
                /*$configup['upload_path']    = FCPATH . '/assets/admin/galeria/';
                   $configup['allowed_types'] = 'jpg|png|gif';
                $this->load->library('upload', $configup);
                if ( ! $this->upload->do_upload('arquivo')) {
                    $error = array('error' => $this->upload->display_errors());
                    redirect(base_url('administration/dashboard', $error));
                } else {
                      $fotos['path'] = $this->upload->data('full_path');
                    $fotos['ft_nome'] = $this->upload->data('file_name');
                    $fotos['status'] = "A";
                    $this->upload_model->inserirImagens($fotos);
                    redirect(base_url('dashboard'));
                }
             */
             }

        function cadastrarAlbum(){
                $nome = $this->input->post('nomeAlbum');
                $album  = array('id' => NULL, 'album_nome' =>strtolower($nome));
                $path = FCPATH . '/assets/admin/galeria/';
                if (!is_dir($path)) {
                    mkdir($path, 0777, true);
                }
                $dir_exist = true; // flag for checking the directory exist or not
                if (!is_dir($path . strtolower($nome))) {
                    mkdir($path . strtolower($nome), 0777, true);
                    $dir_exist = false; // dir not exist
                }
                $this->db->insert('tb_albuns', $album );
                redirect(base_url('dashboard'));
         }


        function consultarId(){
                $id = $this->input->post('id');
                $this->db->select('*');
                $this->db->from('tb_albuns');
                $this->db->join('tb_galeria', 'tb_galeria.idAlbum = tb_albuns.id');
                $this->db->where('tb_albuns.id', $id);
                $data[] = $this->db->get()->result();
                echo  json_encode($data);
         }

         function primeiraImg(){
                $id = $this->input->post('idAlb');
                $this->db->select('*');
                $this->db->from('tb_albuns');
                $this->db->join('tb_galeria', 'tb_galeria.idAlbum = tb_albuns.id');
                $this->db->where('tb_albuns.id', $id);
                $this->db->order_by('tb_albuns.id', 'DESC');
                $this->db->limit(1);
                $pImg[] = $this->db->get()->result();
                echo  json_encode($pImg);
         }
}

Codigo para upload e consulta de imagens