excludeFromSpider in Spider class does not seem to exclude URL

[petermartin2002]

Hi

I am looking again at the zap java api. And I am writing a regex to exclude jpg, png and gif paths from the spider.

    zapSpider.excludeFromSpider("\\.(?!(jpg|png|gif)$)[a-z]+$");
    zapSpider.spider(myApp.BASE_URL);
    int spiderID = zapSpider.getLastSpiderScanId();

I am wondering if there have been any issues encountered with the regxing previously and if the regex I am giving is valid?