Assigning a creative license to your work is part of the copyright process. To assign copyright implies ownership- you can not license what you do not own. For GSC faculty this is a bit more complex than simply deciding to share (or not share) work you create. Rather than providing a clear answer, here are a set of questions to consider:
The process for adding a creative commons license to your work is relatively easy. CC license chooser. At the chooser, simply answer a few questions, fill in the fields you need, and receive an already formatted HTML code. The HTML code may then be pasted into your course, website, or blog.
You can use creative commons licensed materials as long as you follow the license conditions. One condition of all CC licenses is attribution. Creative Commons has an excellent Best Practices for Attribution of a Photograph page. Below are some examples taken from that page.
For More Information
If you have any doubts or questions, you can read the complete attribution requirements which are spelled out in detail in the legal code of every CC license, eg. http://creativecommons.org/licenses/by/4.0/legalcode#s3a. This chart compares the detailed requirements across all versions of CC licenses.
This is an image from a Creative Commons celebration
It has a:
An OK Attribution
"Creative Commons 10th Birthday Celebration San Francisco" by tvol, used under CC BY / Desaturated from original. NOTE: This is considered a slight alternation of the original photograph.
In general the attribution statement should be placed below or next to the image being attributed. See examples above