Uploading image with Codeigniter Uploading ignored allowed types and file sizes

I have a code to load a user image, my code is working well, but I am getting a problem when checking allowed_types

ie png|jpg

and max_size

.. It does not check for valid type and max size

code:

$this->load->library('upload');
$config['upload_path'] = 'admin/upload/';
$config['allowed_types'] = 'jpg|jpeg';
$config['max_size'] = '100';

$this->load->library('upload', $config);
$this->upload->initialize($config);
$this->upload->set_allowed_types('*');

if (!$this->upload->do_upload('user_image')){ 
    $data = array('msg' => $this->upload->display_errors());
    $flag="1";
}else { 
    $image_path = $this->upload->data();
    $flag="2";
}

      

        
        
        
      

    

Output:

$flag

always set to 2 ... even i downloaded a .png or .gif file and the same problem for max_size