Creative Commons (CC) works differently than copyright restrictions. CC is a public network in which people can use other's works under certain allowances set by the creator. With copyrighted works, where all rights are reserved, you must contact the author to use their work. However, with CC works, the creator may have already stated the allowances for the work. There are six different types of allowances under CC ranging from all rights reserved to giving others the ability to share with everyone. See below the infographic for an example of how to cite CC images. The chart below is a great visual guide on CC, you can visit Creativecommons.org page to read more. You can use their Wiki pages too which will help you learn more about CC.
"Creative Commons licensing help chart" by Foter is licensed under CC BY 3.0