It is a website best practice (and the law) to have full permission to use content or images on your website.
If you do not have express permission to use the photos or content you may have added to your website (or anything digital, for that matter) - beware the infringement attorneys.
A client recently updated their own website with an image that they grabbed off the web. The photo was on the site for maybe 10 days, then taken off when another update was initiated.
Everything was fine, until it wasn't.
Getty Images came calling with a Settlement Demand letter from a Licensing Compliance attorney demanding $834. For one very small photo.
Then client had to hire an attorney to negotiate a settlement amount (and Getty did come down slightly), and then had to remove said image from the website and the server.
How did Getty know? This article is packed with info on the topic: https://womeninbusiness.about.com/od/copyrightlaws/a/Can-I-Ignore-A-Getty-Settlement-Demand-Letter.htm
Next time you're tempted to save time and expense on images, go to one of the stock photography houses and choose something that is in keeping with your images budget. Or ask Six Degrees Studio for assistance.
You'll sleep better at night.
Update: Getty has just opened up the ability to use thousands of their photos for free, as long as their embed credit is used. More information here, courtesy Getty Images.