<?php
$text = '<img src="/d/349822-2/">';
echo $text, PHP_EOL;
'/\d{3,}/',
function ($matches) {
return $matches[0] + 2;
},
$text
);
PD9waHAKCiR0ZXh0ID0gJzxpbWcgc3JjPSIvZC8zNDk4MjItMi8iPic7CmVjaG8gJHRleHQsIFBIUF9FT0w7CmVjaG8gcHJlZ19yZXBsYWNlX2NhbGxiYWNrKAogICAgJy9cZHszLH0vJywKICAgIGZ1bmN0aW9uICgkbWF0Y2hlcykgewogICAgICAgIHJldHVybiAkbWF0Y2hlc1swXSArIDI7CiAgICB9LAogICAgJHRleHQKKTs=