<?php
$html = "https://content-available-to-author-only.com/blog/images/image.png";
return empty($m[1]) ?
'http://w...content-available-to-author-only...e.com/blog' : $m[1] . "/blog"; }, $html);
echo $html;
PD9waHAKCiRodG1sID0gImh0dHBzOi8vY29udGVudC1hdmFpbGFibGUtdG8tYXV0aG9yLW9ubHkuY29tL2Jsb2cvaW1hZ2VzL2ltYWdlLnBuZyI7CiRodG1sID0gcHJlZ19yZXBsYWNlX2NhbGxiYWNrKCdAKGh0dHBzPzovL3d3d1wuZXhhbXBsZVwuY29tKT8vYmxvZ0BpJywgZnVuY3Rpb24oJG0pIHsgCglyZXR1cm4gZW1wdHkoJG1bMV0pID8gJ2h0dHA6Ly93Li4uY29udGVudC1hdmFpbGFibGUtdG8tYXV0aG9yLW9ubHkuLi5lLmNvbS9ibG9nJyA6ICRtWzFdIC4gIi9ibG9nIjsKfSwgJGh0bWwpOwplY2hvICRodG1sOw==