Mozda ovako nesto trazis.
PHP kôd:
$tekst = "fds dsf [img]http://www.google.com/images/nav_logo7.png[/img] dsf
dfs [img]http://www.google.com/images/nav_logo2.png[/img] dfsdf ds
dfs sdsadas[img]http://www.google.com/images/nav_logo3.png[/img] dfsdf ds";
if (preg_match_all("/\[img\](.*)\[\/img\]/i", $tekst, $slike)) {
print_r($slike[1]);
}