here you are returning the whole content, to reference specific parts of a site there are numerous ways:
1) RSS, XML, API feeds - this will provide you with interfaces to quickly retrieve specific options (not always available)
2) scraping and parsing - this is taking parts (or whole site and disregarding parts you are not familiar with). Frowned upon without siteowners permission (espoecially if you are to do this frequently). Its possible to do what you are doing and then 'filter' the returned content to disregard anything BUT the images / itmes you want.
Great chapter on this in http://www.amazon.co.uk/Webbots-Spiders-Screen-Scrapers-Developing/dp/1593273975/ref=sr_1_6?ie=UTF8&qid=1318193937&sr=8-6