How to upload multiple files in codeigniter 3.0.1
By default codeIgniter doesn't support multi-file upload. So you can use this library CodeIgniter Multiple Upload Library
I think you need to change this line:
if (!$this->upload->do_upload('files[]'))to
if (!$this->upload->do_upload('files'))
you did not pass file name to upload function.Try this.
if (!$this->upload->do_upload($_FILES['files']['name'])) { $error =['error' => $this->upload->display_errors()]; $this->load->view('admin/addGallery', $error);}