Extract string inside multi-quoted variable

I've a variable with multiple single quotes and want to extract a string of this.

My Code is:

$image['src'] = addslashes($image['src']);
preg_match('~src=["|\'](.*?)["|\']~', $image['src'], $matches);
$image['src'] = $matches[1];

$image['src'] contains this string:

tooltip_html(this, '<div style="display: block; width: 262px"><img src="https://url.com/var/galerie/15773_262.jpg"/></div>');

I thought all would be right but $image['src'] returns null. The addslashes method works fine and returns this:

tooltip_html(this, \'<div style="display: block; width: 262px"><img src="https://url.com/var/galerie/15773_262.jpg"/></div>\');

I don't get the problem in here, did I miss something?

=====UPDATE======

The whole code:

<?php
 error_reporting(E_ALL);
 header("Content-Type: application/json", true);
 define('SITE', 'https://akipa-autohandel.autrado.de/');
 include_once('simple_html_dom.php');

 /**
   * Create CDATA-Method for XML Output
   */

 class SimpleXMLExtended extends SimpleXMLElement {
    public function addCData($cdata_text) {
        $node = dom_import_simplexml($this); 
        $no   = $node->ownerDocument; 
        $node->appendChild($no->createCDATASection($cdata_text)); 
    }
 }
 /**  
   * Get a web file (HTML, XHTML, XML, image, etc.) from a URL.  Return an
   * array containing the HTTP server response header fields and content.
   */
 function get_web_page( $url ) {
    $user_agent='Mozilla/5.0 (Windows NT 6.1; rv:8.0) Gecko/20100101 Firefox/8.0';
    $options = array(
        CURLOPT_CUSTOMREQUEST  =>"GET",        //set request type post or get
        CURLOPT_POST           =>false,        //set to GET
        CURLOPT_USERAGENT      => $user_agent, //set user agent
        CURLOPT_COOKIEFILE     =>"cookie.txt", //set cookie file
        CURLOPT_COOKIEJAR      =>"cookie.txt", //set cookie jar
        CURLOPT_RETURNTRANSFER => true,     // return web page
        CURLOPT_HEADER         => false,    // don't return headers
        CURLOPT_FOLLOWLOCATION => true,     // follow redirects
        CURLOPT_ENCODING       => "",       // handle all encodings
        CURLOPT_AUTOREFERER    => true,     // set referer on redirect
        CURLOPT_CONNECTTIMEOUT => 120,      // timeout on connect
        CURLOPT_TIMEOUT        => 120,      // timeout on response
        CURLOPT_MAXREDIRS      => 10,       // stop after 10 redirects
    );

    $ch      = curl_init( $url );
    curl_setopt_array( $ch, $options );
    $content = curl_exec( $ch );
    $err     = curl_errno( $ch );
    $errmsg  = curl_error( $ch );
    $header  = curl_getinfo( $ch );

    if($content === FALSE) {
        // when output is false it can't be used in str_get_html()
        // output a proper error message in such cases
        echo 'output error';
        die(curl_error($ch));
    }

    curl_close( $ch );
    $header['errno']   = $err;
    $header['errmsg']  = $errmsg;
    $header['content'] = $content;
    return $header;
 }

 function renderPage( $uri ) {
    $rendering = get_web_page( $uri );
        if ( $rendering['errno'] != 0 )
            echo 'bad url, timeout, redirect loop';

        if ( $rendering['http_code'] != 200 )
            echo 'no page, no permissions, no service';

    $content = $rendering['content'];

    if(!empty($content)) {
        $parsing = str_get_html($content);
    }

    return $parsing;
 }

 /**  
   * Get all current car data of the selected autrado site
   */
    function models() {
                $paramURI = SITE . 'schnellsuche.php?suche_hersteller=14&suche_modell=&suche_from=form&suche_action=suche&itemsperpage=500';
                $content = renderPage($paramURI);

                foreach ($content->find('tr[class*=fahrzeugliste]') as $auto) { 
                    $item['src']    = $auto->find('a[onmouseover]', 0)->onmouseover;

                    preg_match('~src=["\'](.*?)["\']~', $item['src'], $matches);
                    echo $matches[1];
                }
        }

if(isset($_POST['action']) && !empty($_POST['action'])) {
    $action = $_POST['action'];
    if((string) $action == 'test') {
        $output = models();
        json_encode($output);
    }
}
 ?>

The content of $image['src'] is not as you wrote above. I've run now your script and the content is:

tooltip_html(this, '<div style="display: block; width: 262px"><img src="http://server12.autrado.de/autradogalerie_copy/var/galerie/127915_262.jpg" /></div>');

It will work if you add the following line before the preg_match:

$item['src']= html_entity_decode($item['src']);