Wordpress function str_replace Yardim

embed height="322" width="512" src="http://d.yimg.com/static.video.yahoo.com/yep/YV_YEP.swf?ver=2.2.46" type="application/x-shockwave-flash" flashvars="id=15914254&amp;vid=&amp;lang=en-us&amp;intl=us&amp;thumbUrl=http%3A//l.yimg.com/a/p/i/bcst/videosearch/11679/94587168.jpeg&amp;embed=1" bgcolor="#000000" allowscriptaccess="always" allowfullscreen="true"></embed></div>


Yahoo Videolarindaki thumb resmi degistirmek icin yukardaki kirmizi olan yeri replace ederek nasil kendi thumb resmim ile degistirebilir?
Buda benim thum resmim

http%3A//l.yimg.com/a/p/i/bcst/videosearch/11679/94587168.jpeg

Asagidaki functionu degisitrmeye calistim ama bir turlu yapamadim
Orjinal hali..

function image_scrape($entry) {
	// don't scrape the image for the feed
	if (is_feed()) { return $entry; }
	//remove image tag
	$entry = preg_replace('/<img [^/>]*src=(\"|\').+?(\1)[^>]*\/*>/','', $entry); /* */
	//remove any empty tags left by the scrape.
	$entry = str_replace('<p> </p>', '', $entry);
	$entry = preg_replace( '|< ([a-z]+)[^>]*>\s*|i', '', $entry );
	$entry = preg_replace( '|< ([a-z]+)[^>]*>\s*|i', '', $entry );
	$entry = preg_replace( '|< ([a-z]+)[^>]*>\s*|i', '', $entry );
	return $entry;
}

$yerine_koyulacak = 'hede.jpg';
$cikti = preg_replace('#thumbUrl=(.*?)&amp;#', 'thumbUrl=' . $yerine_koyulacak . '&amp;', '#embed height="322" width="512" src="http://d.yimg.com/static.video.yahoo.com/yep/YV_YEP.swf?ver=2.2.46" type="application/x-shockwave-flash" flashvars="id=15914254&amp;vid=&amp;lang=en-us&amp;intl=us&amp;thumbUrl=http%3A//l.yimg.com/a/p/i/bcst/videosearch/11679/94587168.jpeg&amp;embed=1" bgcolor="#000000" allowscriptaccess="always" allowfullscreen="true"></embed></div>#');
echo $cikti;

Sagol devturkeli

ama benim istedigim wp functionlari ile calismasi mesala konu eklerken konuyu yayinladigimda oto olarak degismis olmasi lazim kodlarin