here image updated on database but not in directory - codeigniter

Question

here controller page, here image name gets inserted into the database but the image does not go to the corresponding directory
if(isset($_POST['submit']))
{
$config['upload_path'] = './upload/';
$config['allowed_types'] = 'gif|jpg|png|jpeg|pdf|mp4';
$this->load->library('upload', $config);
$this->upload->initialize($config);
$data = array
(
'student_name' => $this->input->post('dname'),
'student_email' => $this->input->post('demail'),
'student_mobile' => $this->input->post('dmobile'),
'student_address' => $this->input->post('daddress'),
'picture' => $_FILES['picture']['name']
);
}
$insertuserdata=$this->Inserts_model->form_insert($data);
here view page
<form action="<?php echo site_url('Insert_ctrl/index/'); ?>"
method="post" enctype="multipart/form-data">
<label>NAME</label>
<input type="text" name="dname" required onkeyup="textt(this)"
id="name"><br>
<label>email</label>
<label>Picture</label>
<input class="form-control" type="file" name="picture" /><br>
<input type="submit" name="submit" value ="submit">
</form>

Answer 1

You should try like this
$config['upload_path'] = './upload/';
$config['allowed_types'] = 'gif|jpg|png|jpeg|pdf|mp4';
$this->load->library('upload', $config);
$this->upload->initialize($config);
if(!$this->upload->do_upload('picture'))
{
$error = array('error' => $this->upload->display_errors());
print_r($error);
}
else{
$data = array('upload_data' => $this->upload->data());
print_r($data);
}