queue.enqueue_read_image(img, compute::dim(0), compute::dim(1), &first_pixel);
BOOST_CHECK_EQUAL(first_pixel, compute::uchar_(128));
}
queue.enqueue_read_image(img, compute::dim(0), compute::dim(1), &first_pixel);
BOOST_CHECK_EQUAL(first_pixel, compute::uchar_(128));
}