This license is the successor of two previous licenses, the Standard Free License and the Free Photo License.
This is only a summary of the license. The legal text contains the terms of the license.
Simple Free License
You can use and share the material for any purpose, as long as you give credit.
In most cases, simply providing a link to the original is enough. (Specifically, the original has to include a link to this license, or you can include one yourself.)