<?php
 
$str = array(
    '<img alt="test" src="http://w...content-available-to-author-only...n.com/t/img.png" title="test title" />',
	'<img src="http://w...content-available-to-author-only...n.com/img.png">',
	'<img src="http://w...content-available-to-author-only...n.com/t/53538/ezgze4/img.png" />',
	'<img alt="test" src="someimg.png" style="blah" title="test title" />',
);
 
foreach($str as $t) {
	echo preg_replace('/<img.*src="http:\/\/www.theblacklisteddomain.com(.*?)".*\/?>/', 'replaced', $t) . PHP_EOL;
}
?>

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