File Upload Function By CI

Controller
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if ( !empty($_FILES['gallery_images']['name'] )) 
{
	$gallery_images = $this->Gallery_model->uploadImage('gallery_images','gallery_images','gif|jpg|png',1);
	$attachment  = $gallery_images['file_name'];
	if ( $gallery_images['file_name'] == '' ) 
	{
	    $this->session->set_flashdata('FlsMsg',$this->alert->danger($gallery_images['upload_error']));
		redirect( 'Gallery/gallery_form' );
	}
	}
	else
	{
	    $attachment = '';
	}

Model
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public function uploadImage($field_name,$path,$type=null,$thumb=null,$width=null,$height=null,$size=null)
    {
        $path = './assets/images/'.$path.'/';
        makedir($path);
        $config['upload_path'] = $path;
        $config['allowed_types'] = $type;
        $config['file_ext_tolower'] = true;
        $config['max_size']	= $size;
        $config['max_width']  = $width;
        $config['max_height']  = $height;   

        $this->load->library('upload', $config);
        if (!$this->upload->do_upload($field_name)){
             $data['upload_error'] = $this->upload->display_errors();
             $data['file_name'] = '';
             return $data;
        }
        else{
            $data = $this->upload->data();
            if($thumb)
            {
               $thumbpath = './assets/images/post_thumb/';
               makedir($thumbpath);
               $resize['image_library'] = 'gd2';
               $resize['source_image'] = $path.$data['file_name'];
               $resize['create_thumb'] = FALSE;
               $resize['new_image'] = $thumbpath.'/'.$data['file_name'];
               $resize['maintain_ratio'] = true;
               $resize['width'] = 255;
               $resize['height'] = 255;

                $this->load->library('image_lib', $resize);

                if ( ! $this->image_lib->resize()){
                    echo $this->image_lib->display_errors();
                }
            }
            return $data;
        }
    }