regex help regarding img tags

[Jenta]

to prevent hotlinking to unauthorized domains im trying to limit the img tag to only a couple
mysite.com and somefreeimagesite.com

functions_bbcodeparse.php, you have this

PHP Code:

// do [img]https://vborg.vbsupport.ru/[/img]
        $bbcode = preg_replace('#\[img\]\s*(https?://([^<>*"' . iif(!$vboptions['allowdynimg'], '?&') . ']+|[a-z0-9/\\._\- !]+))\[/img\]#iUe', "handle_bbcode_img_match('\\1')", $bbcode); 


i have modified it to this and it makes it so only mysite.com will work
(added www.mysite.com after the http:// part )

PHP Code:

// do [img]https://vborg.vbsupport.ru/[/img]
        $bbcode = preg_replace('#\[img\]\s*(http://www.mysite.com([^<>*"' . iif(!$vboptions['allowdynimg'], '?&') . ']+|[a-z0-9/\\._\- !]+))\[/img\]#iUe', "handle_bbcode_img_match('\\1')", $bbcode); 


how would i go about adding an additional domain?
the urls from the 2nd domain are in this format:

http://img(somenumbers and other stuff).cx

just making it work with

http://img

will be fine if thats all that can be done

ideally, i would like for it to jumble up anything posted that does not fit the two formats
like if someone does

[img]http://google.com/image.type[/img]

it will not parse it but will also replace it with some random characters like

[img]hqroiqrq9212o424229uy92r2252[/img]