From MakeUseOf.com:

FreezePage lets you take snapshots of web pages and store them for later reference. What makes FreezePage different from other screenshot capture tools is that in addition to screenshots it also saves the exact date and time, page size and more. Thus it can be used as an independent third party tool to provide evidence on web copyright issues. Whether someone is stealing your content, illegally distributing your images, using your logos ... you can just freeze the page and use it as an evidence.