Have you ever drawn a picture, written a song, taken a photograph, or choreographed a dance? As soon as you make something you own the copyright to that image. Copyright protects your work from being taken by someone else and used in ways that you wouldn’t want such as selling it, changing it, or otherwise using it without your permission. As the artist, poet, musician, or other creative person you want your work to be protected and respected, right? The same is true for everyone else.
If you want to include something that someone else has made on your website or blog, you need to make sure that you have their permission first. Using work without permission is a form of stealing. Creative Commons was invented to help artists collaborate and share their work with others in ways that do not violate copyright laws. It is a kind of license that creative people can apply to their work that lets you know what permissions you have. For example, the photograph at the top of this page is licensed under Creative Commons. In order to use it on my blog I had to give the artist credit (see the line at the bottom of the page). Images with the cc symbol are licensed under Creative Commons. Sites such as photopin, creativecommons.org, flickrcc.net, or pics4learning allow you to search for free images with Creative Commons licensing.
Wanna Work Together? video from the Creative Commons website