preg_replace_callback

<?php

$content = '<img src="https://img.fotofaze.com/img/ikan.jpg"><br>'.
    '<img src="https://img.fotofaze.com/img/kucing.jpg"><br>'.
    '<img src="https://img.fotofaze.com/img/harimau.jpg"><br>';

function img_replace_callback($matches) {
    $url = $matches[1];
    echo $url;
    $domains = array(
        "img01.fotofaze.com",
        "img02.fotofaze.com",
        "img03.fotofaze.com",
        "img04.fotofaze.com",
        "img05.fotofaze.com"
    );

    $ori_host = parse_url($url, PHP_URL_HOST);
    $index = crc32($url) % count($domains);
    if ($ori_host == 'img.fotofaze.com') {
        return 'src="'.str_replace('img.fotofaze.com', $domains[$index], $url).'"';
    }
    return 'src="'.$url.'"';
}

$counter = 0;
function replace_img_domain($text) {
    global $counter;
    $text1 = preg_replace_callback(
        '|src="(^"*)"|' ,
        'img_replace_callback',
        $text,
        $counter
    );
    return $text1;
}


echo '<pre>'.$counter."\n";
var_dump(replace_img_domain($content));
echo '</pre>';