Output different images for each page

page_image.php

<?php
$defaultPage = 'main';
$page = isset($_GET['page']) ? $_GET['page'] : $defaultPage; // /page/{$page}

$imageCount = [
    'main'       => 5,
    'click_prot' => 6,
    'request'    => 1,
    'news_ad'    => 1,
    'info'       => 1,
];

if(array_key_exists($page, $imageCount) === false) {
    $page = $defaultPage;
}

for($i = 1; $i <= $imageCount[$page]; $i++) {
    echo "<img src='/img/pages/{$page}/".str_pad($i, 2, "0", STR_PAD_LEFT).".jpg' />\n";
}