$config['image_library']  = 'ImageMagick';
        $config['library_path']   = '/usr/bin/';
        $config['create_thumb']   = TRUE;
        $config['maintain_ratio'] = FALSE;
        $this->load->library('image_lib', $config);
        $dimensions[0] = array('x'=>171, 'y'=>118, 'dir'=>'small');
        $dimensions[1] = array('x'=>154, 'y'=>105, 'dir'=>'medium');
        $dimensions[2] = array('x'=>312, 'y'=>164, 'dir'=>'large');
        for ($i=0; $i<3;$i++){
            $filesize = filesize($filename);
            $config['image_library']  = 'ImageMagick';
            $config['library_path']   = '/usr/bin/';
            $config['source_image']   = $filename;
            $config['create_thumb']   = TRUE;
            $config['maintain_ratio'] = FALSE;
            $config['width'] = $dimensions[$i]['x'];
            $config['master_dim'] = 'width';

            $this->image_lib->test();
            $this->image_lib->initialize($config);
            $this->image_lib->resize();

            /* This function saves the image in an Amazon S3 Bucket */
            $this->saveThumbnail($imageid, $ext, $dimensions[$i]['dir'], $i);
        }