imagelib thourgh class in codeigniter

1$config['image_library'] = 'gd2';
2$config['source_image'] = '/path/to/image/mypic.jpg';
3$config['create_thumb'] = TRUE;
4$config['maintain_ratio'] = TRUE;
5$config['width']         = 75;
6$config['height']       = 50;
7
8$this->load->library('image_lib', $config);
9
10$this->image_lib->resize();