Guys, be very very careful. As the site owner you will be liable if you do not own the right to any picture that displays on your website - there is even a case on an RSS feed. And getty images ect will charge you an arm and a leg.
As said - the SITE owner will be liable - not the person that made the site, so if you have had a site built ask the designer where they got the images from. Do not think your site is too small to be noticed - they use a robotic crawler similar to google to even spot PARTS of a picture.