problem replacing image path using regex

[synfield]

I have a image tag e.g. <img src="../news/190/mlmeg.html" class="blkthin"> and I want to replace this with the image file name I have just uploaded i.e. <img src="foo.jpg" class="blkthin">

I read the above html file into a the $contents variable.

I use preg_replace function in the file upload script using the uploaded file name variable i.e.

$search = array(
      "/<img src=(http(s?):\/\/)?(www\.)?([\w\.]+)\{$userfile_name}/is"
    );
	$replace = array("<img src=\"$userfile_name\" alt=\"$1");

 $contents = preg_replace($search, $replace, $contents);       

Could someone point out where the problem is in my regex evaluation.

Regards

Synfield