ImageUtil::checkImageContent false positive

// search for javascript
        if (strstr($content, 'script') || strstr($content, 'javascript') || strstr($content, 'expression(')) return false;

               <rdf:li rdf:parseType="Resource">
                  <stEvt:action>converted</stEvt:action>
                  <stEvt:parameters>from application/postscript to application/vnd.adobe.illustrator</stEvt:parameters>
               </rdf:li>