View file img/code.php

<?php
session_name('SID') . session_start();
$code = random_int(11111, 99999);
$_SESSION['code'] = $code;
header('Content-type: image/png');
$img = imagecreate(70, 25);
$ind = 0;
imagecolorallocate($img, 255, 255, 255);
for ($i = 0; $i < 5; $i++) {
    $ind+=10;
    $code_r = substr($code, $i, 1);
    $color = imagecolorallocatealpha($img, random_int(50, 210), random_int(50, 210), random_int(50, 210), random_int(10, 30));
    imagestring($img, 5, $ind, 4, $code_r, $color); 
}
imagepng($img);
imagedestroy($img); 
?>