Image uploading code in Codeigniter

<?php	
	if($this->input->post('submit')) {

		if(!empty($_FILES["product_image"]['name'])) {

			$config = array(
				'upload_path' => "./uploads/products/",
				'allowed_types' => "jpg|jpeg|png|gif",
				'overwrite' => TRUE,
				'max_size' => "2048000", // Can be set to particular file size , here it is 2 MB(2048 Kb)
				//'max_height' => "768",
				//'max_width' => "1024",
				'file_name' => time().'-'.$_FILES["product_image"]['name']
			);
			$uploaderror = '';
			
			$this->load->library('upload', $config);
			if($this->upload->do_upload('product_image'))
			{
				$uploadData = array('upload_data' => $this->upload->data());
				$uploadedfilename = $uploadData['upload_data']['file_name'];
			}
			else
			{
				$uploaderror = $this->upload->display_errors();
			}
		}
	}
?>