define("WIDTH", 300);
define("HEIGHT", 300);
$img = imagecreatetruecolor(WIDTH, HEIGHT);
$white = imagecolorallocate($img, 0xFF, 0xFF, 0xFF);
$yellow = imagecolorallocate($img, 0xFF, 0xFF, 00);
$red = imagecolorallocate($img, 0xFF, 0, 0);
$blue_t = imagecolorallocatealpha($img, 0, 0, 0xFF, 0x40);
imagefill($img, 1, 1, $white);
imageline($img, 0,0, WIDTH-1, HEIGHT-1, $blue_t);
imagefilledrectangle($img, (WIDTH/2)-50, (HEIGHT/2)-50,(WIDTH/2)+50, (HEIGHT/2)+50, $yellow);
header("Content-Type: image/png");
imagepng($img);
?>